No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
Clays and health: An introduction
... Clays are categorised into six groups by the U.S. Bureau of Mines: kaolin, ball clay, fire clay, bentonite, fuller's earth and common clay and shale. Hundreds of uses reveal the utility of clays in very different fields (3) . Kaolin has a wide variety of industrial applications, including paper coating, fiberglass and insulation, rubber, paint, ceramics and chemicals. ...
... The fact that harmful effects of certain clay minerals on human health have also been known for centuries should not be ignored (3) . The production, processing and use of various clay minerals are characterised by particulate emissions in the form of dust, as in the case of mining, stockpiling, crushing, grinding and screening. ...
Clays are among the most important industrially used minerals. Three potential clay mineral mining sites in Saudi Arabia were
chosen, and 21 clay deposit samples were collected. The activity concentrations (average±standard deviation) of the naturally
occurring radioactive materials (NORMs), 238U, 226Ra, 232Th, 228Ra and 40K, were 49±20, 47±23, 34±11, 40±20 and 751 Bq kg−1, respectively. The radiation dose assessments (e.g., absorbed dose rate, nGy h−1; effective dose equivalent, µSv y−1; and effective dose rate due to dust inhalation, µSv y−1) and hazardous indices (e.g., radium equivalent [Ra-eq] value, external hazardous index [Hex], internal hazardous index [Hin] and representative gamma level [Iγ]) were calculated. The wide variations in the activity concentrations of the NORMs according to sampling region could be
due to the origin of the geological formation and the geochemical behaviour of the NORMs. Based on calculated hazardous (external
and internal) indices, there were no expected radiological hazardous impacts of using clay deposits as building materials.
... Clay minerals are abundant in nature and their absorptive capabilities have been exploited in various cosmetics and pharmaceutical formulations [17][18][19][20][21]. The advantages of clay minerals include their natural abundance, low cost, and environmental friendliness. ...
Aquaculture farms in Arkansas, USA routinely battle columnaris disease caused by Flavobacterium covae. Columnaris is prevalent during stressful events such as feed training and when fish are stocked at high densities in holding vats before sale. Kaolin clay was effective in laboratory trials as a treatment for columnaris in catfish. As a result, fish farmers are interested in applying kaolin products but were hesitant as they feared that the high doses of kaolin clay in vats might negatively affect the gills and overall health of fish. Therefore, we evaluated potential clay concentrations that might be used to prophylactically treat fish in vats. The effects of low to excessively high doses (0, 1, 2, 4, or 8 g/L) of kaolin clay (AkuaProTM, Imerys, GA, USA) were evaluated using a 72 h bioassay conducted in static tanks using Micropterus salmoides, Pomoxis nigromaculatus, Lepomis macrochirus, Ictalurus punctatus, Notemigonus crysoleucas, and Pimephales promelas. Results of these trials revealed a 100% survival rate across all six fish species exposed to kaolin clay at concentrations of up to 8 g/L for 48 h (followed by a 24 h recovery period in clean water) with no adverse effects to eyes, skin, gastrointestinal tract, or liver histology noted at any treatment. In addition, Micropterus salmoides analyzed for heavy metals due to exposure to the clay indicated that concentrations did not differ from control fish.
... 13 Owing to these characteristics and to their anionic character, these clay minerals are suitable materials for medical and cosmetic purposes. 14 To improve mechanical and barrier properties of chitosan films for drug carrying and food packaging uses, the chitosan was mixed with limited amounts (up to about 5 wt%) of montmorillonite. [15][16][17] The addition of the montmorillonite (di-octahedral clay mineral of the smectite group) to chitosan resulted in the formation of nanocomposites with efficient bactericidal effects. ...
Properties of the chitosan films can be improved by incorporating clay minerals. So, solvent-cast films of the β-chitosan containing stevensite-rich or kaolinitic-illitic clays (up to 50 mass %) were characterized for their structural and mechanical properties. The effects of molecular weight (MW) and deacetylation degree (DD) of chitosan and the clay/chitosan mass ratio on the inhibition growth of Escherichia coli and Staphylococcus aureus were studied using the response surface methodology (RSM). The films consisted of exfoliated/intercalated or flocculated composites, and the elec-trostatic bonds formed between the functional moieties of the chitosan and the clay particles active sites essentially influenced their mechanical strength. The results of the study using RSM showed that the optimal value of MW required for the inhibition of the bacteria varied according to the film used, and high antibacterial activity necessitated high DD (89-97%).
... On the other hand, that clay-based materials have various therapeutic properties which are highly useful in the treatment of human diseases since prehistoric times (Carretero and Lagaly, 2007). The International Definition of Peloid, approved in the 4th Conference of ISMH (International Society of Medical Hydrology), held in 1949 in Dax, France, defined a peloid as a "natural product (natural sediment) composed of a mixture of mineral water (seawater and lake water included) with organic or inorganic matter that results from either geologic or biologic processes or yet from both processes, and is utilized for therapeutic purposes under the form of packs, compresses or bath". ...
The Caribbean coast is characterized by the presence of mud volcanoes, a secondary phenomenon of volcanism similar to mud diapirs for its development and evolution, but different in terms of geological features and forms. These mud volcanoes are often located close to tectonic faults and oil and gas deposits. Their geological context is dominated by the presence of clay sediments and brackish water, that favors the decomposition of organic material and the formation of methane. Mud volcanoes can thus be an important reservoir of hydrocarbons. This paper aims to fill the existing gap in the knowledge of mud volcanoes (MVs) of Colombia. We analyze the physical and geochemical characteristics of nine onshore mud volcanoes located in the Departments of Atlántico (La Laguna), Bolívar (Las Palomas, La Bonga, Santa Catalina, Yerbabuena, Clemencia, and Membrillal), Cordóba (Los Olivos), and Magdalena (Cañaveral). These structures present a kaolinitic composition, except for La Laguna mud volcano in which smectite is predominant. Apart from tectonic processes, this influences the shape and size of MVs and, also, the type and frequency of eruptions. The abundance of methane in all sites confirms the thermogenic origin of these structures. MVs are often considered landscape attractions as well as a therapeutic resources, but unfortunately they also represent a serious risk for the local communities, due to the frequent unexpected, eruptions, sometimes accompanied by the release of toxic gases or by landslides, that can damage the infrastructures and hurt the population living in the area. The MVs are classified into five vulnerability classes using a novel synthetic index which could improve the understanding of risks associated with the presence of MVs in proximity to towns and infrastructures.
... Clay minerals are mainly used in dermatological clinics and spas. But in cosmetic industry these geoproducts are still a rising field that's why domestic markets are low [10][11]. Montmorillonite, is the one of the oldest clay, initially investigated in the region France so called 'Montmorillon' [12]. ...
Diabetic cardiomyopathy (DCM) can lead to left ventricular hypertrophy, diastolic dysfunction, and systolic dysfunction, or all of these. Gold nanoparticles (AuNPs) have shown anti-hyperglycemic effects in animal models of streptozotocin (STZ)-induced diabetes. This study was designed to address the effects of AuNPs on the animal model of DCM. 48 male adult rats were randomly categorized into 3 groups (n=6-8 / group): control (non-diabetic, ND), diabetic (D), and intraperitoneally treated diabetic rats with 50 nm AuNPs (D+AuNPs; 2,5 mg/kg/day). One single dose injection of 55 mg/kg STZ was used to induce diabetes in the animals. Blood and the left ventricle were collected after seven weeks for assessment. The myocardial mRNA and protein levels of transforming growth factor β1 (TGF-β1) and tumor necrosis factor-α (TNF-α) were evaluated using real-time PCR and immunohistochemistry. The myocardial mRNA level of vascular endothelial growth factor-A (VEGF-A) was measured using real-time PCR. Besides, the myocardial collagen deposition was measured by masson trichrome stain and immunohistochemistry. Rats with DCM showed hyperglycemia, increased myocardial mRNA and protein tissue content of TGF-β1, myocardial mRNA of VEGF-A (P < 0.05), and tended to increase myocardial mRNA and protein tissue content of TNF-α (P < 0.1). An increase in myocardial collagen deposition accompanied these changes. Treatment with AuNPs reduced the above pathological conditions. These results suggest that AuNPs may have therapeutic potential in the treatment of early DCM. Further studies are needed to explore the possible mechanisms by which AuNPs may prevent the development of DCM.
... Clay minerals are mainly used in dermatological clinics and spas. But in cosmetic industry these geoproducts are still a rising field that's why domestic markets are low [10][11]. Montmorillonite, is the one of the oldest clay, initially investigated in the region France so called 'Montmorillon' [12]. ...
An emerging herbal product 'Aloe vera' is most widely utilized for skin treatments due to its gel-components of the plant are known to heal the skin from a variety of minor ailments. In depth experimental attempts with Aloe vera (AV), MMT (Clay) and PVA (Poly vinyl alcohol) blend gel were prepared using the solution cast method. AV is very versatile plant, and its benefits are well known. MMT have gained popularity for internal and external detoxification. PVA is biodegradable material which is generally defined as the polymer which decomposes in the environment friendly atmosphere. The applicability of the evaluated formulations was influenced by the polyvinyl alcohol content due to their ability to alter the formulation viscosity. Their properties, relating mechanism and corresponding applications were deeply investigated. Significant formulation provided exclusive levels of applicability as well as thin-film forming performance, the minimum bare time possible and admirable homogeneity of the green-clay particles and aloe vera on or before dehydrating. Hence, the fundamental stability investigation which may optimize formulation is stable under minimal storage conditions. Furthermore, microbiological stability evaluation indicated that the preservative was efficient in term of avoiding microbial growth dynamics. Profitable statistical tools for the conviction of the nature of various compounds and their concentrations for the responses investigated, allowing the observation of the optimum situations further improvement of green clay and aloe vera peel-off skin masks.
... Clay minerals are mainly used in dermatological clinics and spas. But in cosmetic industry these geoproducts are still a rising field that's why domestic markets are low [10][11]. Montmorillonite, is the one of the oldest clay, initially investigated in the region France so called 'Montmorillon' [12]. ...
An emerging herbal product ‘Aloe vera’ is most widely utilized for skin treatments due to its gel-components of the plant are known to heal the skin from a variety of minor ailments. In depth experimental attempts with Aloe vera (AV), MMT (Clay) and PVA (Poly vinyl alcohol) blend gel were prepared using the solution cast method. AV is very versatile plant, and its benefits are well known. MMT have gained popularity for internal and external detoxification. PVA is biodegradable material which is generally defined as the polymer which decomposes in the environment friendly atmosphere. The applicability of the evaluated formulations was influenced by the polyvinyl alcohol content due to their ability to alter the formulation viscosity. Their properties, relating mechanism and corresponding applications were deeply investigated. Significant formulation provided exclusive levels of applicability as well as thin-film forming performance, the minimum bare time possible and admirable homogeneity of the green-clay particles and aloe vera on or before dehydrating. Hence, the fundamental stability investigation which may optimize formulation is stable under minimal storage conditions. Furthermore, microbiological stability evaluation indicated that the preservative was efficient in term of avoiding microbial growth dynamics. Profitable statistical tools for the conviction of the nature of various compounds and their concentrations for the responses investigated, allowing the observation of the optimum situations further improvement of green clay and aloe vera peel-off skin masks.
... Clay has effectively proven itself in both cosmetology and dermatology [4][5][6][7][8][9][10][11]. Clays have cleansing, moisturizing, soothing, regenerative, anti-inflammatory, sedative, anti-septic and detoxifying effects; they rejuvenate, tone and nourish the skin [9,10,[12][13][14][15][16][17]. ...
Clay has a great biomedical application potential, however there are just a few instrumental studies and the impact of lake clay on the skin has not yet been studied. The DermaLab skin analysis system (Cortex Technology) was used for hydration, elasticity, transepidermal water loss (TEWL) and pH measurements after lake clay facial applications. Research included short-term tests (measurements 20 and 60 min after clay application) and long-term tests (application every 4th day for 3 weeks with measurements 20–24 h post-application). Control measurements and application tests to exclude contact allergy were made beforehand. No volunteer (n = 30) had positive allergic reaction. The matched-pairs design was applied: the right and left parts of forehead were used for the test and control groups. The Wilcoxon signed-rank test (significance level p = 0.001) was applied for statistical analysis. There were statistically significant pH changes demonstrated during the short-term measurements. The long-term measurements provided data that clay significantly improves skin hydration and elasticity.
... Minerals are widely used in the pharmaceutical industry as lubricants, desiccants, disintegrating, diluents, binders, pigments, and opacifiers, as well as emulsifying, thickening, isotonic, agents, and anticaking agents, and flavor correctors and carriers of active ingredients 6 . In addition, also clays have been employed as carriers for organic molecules in cosmetics and drugs, as a catalyst support 7 and as excipient in solid, liquid, and semi-solid pharmaceutical, such as gels, for example 1,6,8,9 . Gels are semisolid systems composed of two phases: the liquid dispersing phase and the solid dispersed phase 10 . ...
The clay minerals have characteristics and properties that allow their applicability in the cosmetic area, being incorporated into formulations as an active principle. Therefore, the aim of this work is characterizing and evaluating the influence of a clay from Miracema do Norte, Tocantins, Brazil, named Clay V, on the physicochemical characteristics of a hydrophilic gel of Aristoflex®, a copolymer of the neutralized acryloyldimethyltaurate and vinylpyrrolidone sulphonic acid. Clay V was decontaminated and characterized through microbiological evaluation, crystalline phases present by X-Ray Diffraction (XRD), chemical composition by X-Ray Fluorescence (XRF), thermogravimetric analysis (TGA) and granulometric distribution by sieving. Gels were prepared using Clay V with particles in the range ≤ 180 μm in three different concentrations: 1%, 3% and 5% (w/w) and a standard gel without clay. The formulations were evaluated according to organoleptic characteristics, pH, viscosity, spreadability and the centrifugation test. The microbiological evaluation showed that the clay sample is in compliance with the parameters established by the legislation. The following mineral phases were identified by XRD: kaolinite, illite, vermiculite and quartz, mainly composed of silica and alumina according to XRF. Thermal analysis showed that the clay has two thermal decomposition reactions, the largest being 547.6°C. The granulometric analysis identified that the largest fraction (63.22%) was of particles with sizes greater than 710 μm. The organoleptic characteristics presented by the formulations were suitable, with characteristic gel odor, homogeneous appearance, soft and refreshing texture and staining based on the concentration of Clay V used. The obtained pH values were within the range between 5.5 and 6.5, and it was verified that the gel has high spreadability, distributing evenly on the skin. The values obtained for viscosity showed that the formulations are non-Newtonian fluids with pseudoplastic behavior. The centrifugation test showed that the formulations are stable, with no phase separation. The results obtained with the tests showed that the natural clay V material is beneficial in cosmetic products and can be used for incorporation in cosmetic gel formulations of Aristoflex® type.
... The fact that harmful effects of certain clay minerals on human health have also been known for centuries should not be ignored (Carretero and Lagaly, 2007). The production, processing and use of various clay minerals are characterized by particulate emissions in the form of dust, as in the case of mining, stockpiling, crushing, grinding and screening. ...
The research involved the diagnosis of the kaolinite, bentonite and attapulgite clays in formations of Western Desert from Iraq by means of an X-Ray Diffraction device (XRD), and their total content of uranium (U) and thorium(Th) by XRF. As well as contamination status assessment of these clays by U and Th by means of simple pollution index(PI) and Geo-accumulation index (Igeo). XRD showed the presence of kaolinite by 83% in the kaolinite clays and 15% bentonite with75% montmorillonite in bentonite clays, as well as 55% of palygorskite and 30% sepiolite in attapulgite clays. XRF results appeared content of U and Th were 3.8, 26.6; 3.3, 7.2 and 7.0, 6.2 mg kg-1 in kaolinite, bentonite and attapulgite clays respectively. PI of U in kaolinite was 1.36, Bentonite: 1.18, attapulgite: 2.5 and in pollution levels ranged from low to moderate. While it was high pollution level of Th in the kaolinite clays (3.59). The results of Igeo indicated that there was a role for human activity inputs in pollution of study clays, with values were 0.15, 0.24; 0.50, 0.73; 0.20 and 0.17 of U and Th in kaolinite, bentonite and attapulgite respectively.
... Bentonites are formed by highly colloidal and plastic clays composed mainly of montmorillonite, a clay mineral of the smectite group (Phillips et al., 1995;WHO, 2005;Bergaya and Lagaly, 2013). Hundreds of uses reveal the utility of clays in very different fields (Carretero and Lagaly, 2007). Bentonites are broadly distributed around the world, but approximately 90% of the world's bentonite production is concentrated in 22 countries (WHO, 2005). ...
Since 2013, bentonite in the form of dioctahedral smectite is an additive authorised in the EU as a substance for the reduction of the contamination of feed by aflatoxins. Several studies indicate a big difference in the effectiveness of smectites in sequestering aflatoxins. A clear correlation between mineralogical and physico-chemical properties of smectites and aflatoxin adsorption has not been well established. In the effort to identify the most critical mineralogical, chemical, and physical properties that affect aflatoxin adsorption by smectites, 29 samples of bentonites obtained from different sources around the world were evaluated. "As received" samples were divided into two main groups, i.e. hydrothermal (n=14) and sedimentary (n=15) bentonites depending on their geological origin. The characterization studies showed that all samples contained dioctahedral smectite as major mineral; a moderate CEC value (60-116 cmol/kg); the presence of iron; a small organic matter content; a near-neutral pH; and a fine and uniform particle size (< 45μm). They differed substantially in their sodium, calcium and magnesium contents, and in the swelling properties depending on the geological origin. Several in vitro adsorption studies showed that they also differed in a significant manner in adsorbing aflatoxin B 1 (AFB 1). A correlation between geological origin and AFB 1 adsorption capacity was found (p < 0.001), being sedimentary smectites significantly more effective than hydrothermal ones in adsorbing the toxin at different pH values. The extent of AFB 1 adsorption by all samples was negatively and linearly correlated to the extent of desorption, and sedimentary smectites were significantly more effective than hydrothermal smectites in keeping bound the adsorbed fraction of the toxin (p < 0.001). In addition, correlation studies using the Pearson statistical method showed a significant relationship among some physico-chemical properties of smectites and the amounts of adsorbed toxin. In particular, AFB 1 adsorption by smectites correlated positively with sodium content and swell index, but negatively with d001-value, magnesium and calcium contents. In conclusion, it seems that the geological origin of smectite is a useful guide for the selection of bentonites for AFB 1 detoxification. Sedimentary bentonites containing sodium/swelling-smectite should be preferred to hydrothermal samples as potential aflatoxin binders. Taking into account the geographical origin of our samples, this approach should be applicable to bentonites worldwide.
... The adsorption isotherms of the lake sediments studied can also be divided into two groups. Lake Pauguļi and lake Zeiļi clay sample Z2. 9 and Z2.8 isotherms correspond to type IV, but Z4.8, Z2.7 and lake Plusons sample isotherms correspond to type II according to IUPAC classification [29] (Figure 4). ...
Sedimentary clay of three Latvia region of Latgale lakes – Zeiļi, Pauguļi and Plusons – was investigated. Mineral composition was determined by X-ray diffraction, the average size and size distribution of particles by dynamic light scattering method, specific surface by Brunauer-Emmett-Teller method, and adsorption characteristics after methylene blue: adsorption capacity and adsorption isotherms. The samples contained typical clay crystalline phases – illite, kaolinite – and rock forming minerals – quartz, dolomite, calcite, plagioclase, albite, and enstatite. The granulometric content of samples is mostly characterised by silt (2 – 63 µm) and clay (< 2 µm) fractions. Specific surface area varied from 9.45 to 20.68 m2/g. The adsorption capacity of lake clay was in the range of 25.8 – 45.8 mg/g. Clay adsorption isotherms were represented by the second and fifth type curves according to the International Union of Pure and Applied Chemistry (IUPAC) classification, indicating the presence of micro- and macroporous space in samples and strong intermolecular interactions. The difference between properties of clay in different lakes and at different depths and their influencing factors have been clarified. The information obtained enables to predict the areas of use of clay in cosmetics and medical treatment.
... On the other hand, the use of natural-product antibiotics such as essential oils, derivatives of Chitosan [5], and novel strategies in the pharmaceutical industry like the preparation of composite from natural clays [6] have been widely studied as well. Clay minerals have very different physical and chemical properties [7]. Their uses in new pharmaceutical formulations, especially for reducing release of protonable drugs are due to their suitability surface area, sorptive capacity, chemical inertness, and low or ineffectual toxicity. ...
Inthiswork,inorderto preparebiocomposites ofciprofloxacin- montmorillonite/N,N,N-triethyl chitosan(CMC/ TEC and CMC׳/TEC), ciprofloxacin was intercalated into the Na+-montmorillonite layers in two different pHs and coated with N,N,N-triethyl chitosan. XRD and FT-IR data demonstrated that ciprofloxacin (CIP) diffused among the layers of montmorillonite. The prepared biocomposites were further characterised by TG, SEM, BET, DSC, and disk diffusion method to investigate antibacterial activity against Staphylococcus aureus as well. Coated composites with N,N,N-triethyl chitosan possessed efficiency of the drug encapsulation, and controlled the release of drug from the biocomposites in comparison with composites without N,N,N-triethyl chitosan. Study of antibacterial activities of two biocomposites of CMC1/TEC and CMC2/TEC with lower release rates and lower concentrations of CIP than other biocomposites revealed that likely N,N,N-triethyl chitosan could considerably help to reduce the consumption of ciprofloxacin. By doing more researches on other bacterial strains and performing advanced tests on our own biocomposites, N,N,N-triethyl chitosan can probably be proved as a suitable candidate for a substitute in biomedical activities.
... BC, formed from weathering of volcanic ash in the presence of water, is an absorbent aluminium phyllosilicate clay consisting mostly of smectite [52]. Owing to its adsorptive and absorptive capabilities and cation exchange capacity, it has been applied in health care for a variety of purposes including wound healing and infection control [53][54][55], skin protection [56], cosmetics [57] and rheumatism treatment [58]. Moreover, BC has been applied in heavy metal ion adsorption [59] and removal of organic pollutants from water [60]. ...
Incorporating activated bentonite clay (BC) into electrospun nanofibres is an established strategy for modulating adsorption behaviour. In the present study, naturally occurring calcium BC was completely activated to sodium BC with a 4 wt.% sodium carbonate (Na2CO3)/BC ratio. Composite nanofibre webs were produced from cellulose acetate (CA)/BC spinning solutions using free surface electrospinning and the effect of BC loadings on viscosity, surface tension and electrical conductivity prior to spinning were studied. Chemical and thermal analyses were conducted on as-spun fibres, and SEM and TEM revealed a nanofibrous morphology consisting of an inter-penetrating network of fibres and semi-spherical features resembling jellyfish with an internal core of BC.
... Minerals are widely used in the pharmaceutical industry as lubricants, desiccants, disintegrating, diluents, binders, pigments, and opacifiers, as well as emulsifying, thickening, isotonic, agents, and anticaking agents, and flavor correctors and carriers of active ingredients 6 . In addition, also clays have been employed as carriers for organic molecules in cosmetics and drugs, as a catalyst support 7 and as excipient in solid, liquid, and semi-solid pharmaceutical, such as gels, for example 1,6,8,9 . Gels are semisolid systems composed of two phases: the liquid dispersing phase and the solid dispersed phase 10 . ...
As argilas são minerais naturais, terrosos, constituídos por partículas ou cristais em geral de tamanho inferior a 2 μm (1). São silicatos de alumínio, ferro e magnésio hidratados, com estruturas cristalinas em camadas (2). A utilização de argilas como matéria-prima em diversas áreas, incluindo a cosmetologia, se deve principalmente à necessidade do uso de materiais que não sejam agressivos ao meio ambiente. Além disso, são compostos de baixo custo e abundantes no mundo inteiro (1). Os argilominerais possuem variadas propriedades químicas e físicas que permitem sua utilização para diversas funções em cosméticos (3). Devido à sua capacidade de adsorção, a principal função das argilas em formulações cosméticas é como princípio ativo (4). Suas características singulares permitem a inclusão em diferentes veículos cosméticos, como os géis (3). RESULTADOS Os resultados obtidos com os testes demonstraram que a argila V possui potencial de aplicação em produtos cosméticos, podendo ser utilizada para incorporação em formulações em gel do tipo Aristoflex ®. Verificou-se ainda que a concentração de argila utilizada interfere muito pouco nos parâmetros de uma formulação cosmética. (1) GOMES C. F. Argilas: O que são e para que servem. Lisboa: Fundação Calouste Gulbenkian, 1988. 457 p. (2) COELHO, A. C. V.; SANTOS, P. S.. Argilas especiais: o que são, caracterização e propriedades. Química Nova, São Paulo, v. 30, n. 1, p. 146-152, 27 jan. 2006. (3) MAESEN T.; KUPERMAN A. E.; UCKUNG I. J. Cosmetic and personal care products containing synthetic magnesium alumino-silicate clays. US nº 8652447, 18 dez. 2008, 18 fev. 2014. (4) CARRETERO, M. I. Clay minerals and their beneficial effects upon human health.
... Beneficial properties of clays to human health and their therapeutic effects have received great interest since prehistoric times. Nowadays, clay minerals are applied in spa and beauty therapy, as well as in pharmaceutical and clinical applications [1][2]. ...
New vanadium supported onto mixed molybdenum-titanium pillared clay catalysts “V/(Mo-Ti)-PILCs” with variable quantities of Mo were investigated for the low temperature SCR-NO by NH3. The (Mo-Ti)-PILC supports, prepared by co-intercalation route, and the V/(Mo-Ti)-PILC catalysts, obtained by the impregnation method, have been characterized by means of XRD, N2 adsorption-desorption, IR-spectroscopy, NH3-TPD and H2-TPR. The results have shown the success of the intercalation process through the increase of the basal spacing, the surface area and the porosity of the clay. The simultaneous incorporation of Mo-Ti cationic species and the vanadium deposition have successfully modified the acidic and the redox properties of the pillared materials. In SCR-NO by NH3, the NO conversion was significantly increased, especially at low temperature, after the addition of vanadium. Over the catalyst containing 4 wt% of Mo and 2 wt% of V, NO conversion reached 50% at around 250 °C and exceeded 85% at 400 °C with 100% N2 selectivity. For higher Mo content (8 wt%), N2O formation, in trace amount, was observed above 375 ° C.
... In the pharmaceutical domain, clays have been employed as carriers for organic molecules in cosmetics and drugs, as a catalyst support (Zhang et al., 2011) and as excipient in solid, liquid, and semi-solid pharmaceutical forms (Carretero, 2002;Carretero and Lagaly, 2007;López-Galindo et al., 2007). There is a growing interest in the use of clays based on the search for abundant and low-priced materials that when disposed of, do not harm the environment (Bergaya et al., 2006). ...
Clays are materials originated from rock decomposition, made up of clay minerals and non-clayish minerals. Their applicability in the field of cosmetics depends on their chemical and mineralogical composition. In view of their huge bioburden there is the need to submit them to effective decontamination before they are incorporated into cosmetics. The present work involved the characterization of four different samples of clays originated from the sand extraction residue of mining activities in the hinterland of São Paulo state, Brazil. Characterization was performed with the aid of tools like X-ray fluorescence (XRF), X-ray diffraction (XRD), thermogravimetric analysis (TGA/DTA), particle size distribution by laser dispersion, surface area (BET method) and Fourier transform infrared spectroscopy (FTIR). Besides, it aims to evaluate the bioburden of these clays, as well as to propose a method for the decontamination of these samples. The average particle diameter varied from 3.6 to 24.1 μm, kaolinite and illite being the main mineralogical phases to be identified. The proposed method for decontamination employed a combination of ethanol 70% and dry heat at 120 °C in an oven for 24 h. The decontamination was effective in reducing samples bioburden, leaving the clays within the limits required for cosmetics application.
... Les résultats de l'étude de l'interaction des sols et des plantes dans les compartiments gastriques et intestinaux suggèrent que les sols optimisent les propriétés pharmacologiques de la fraction gastrique bio-disponible (Klein, 2008). Ces travaux importants sur l'animal ouvrent la voie à leur adaptation humaine et sont très prometteurs (Abrahams, 2003 ;Wilson, 2003 ;Choy et al., 2007 ;Carretero et Lagaly, 2007 ;Viseras, 2007 ;Centi et Perathoner, 2008 ;Phillips et al., 2008). sonnels très variés, concrétisée en 2010 par un enseignement universitaire spécialisé devenu nécessaire au niveau master (International Master of Advanced Clay Science -IMACS, Poitiers) est essentielle. ...
... Human beings found various applications of layered clay minerals since prehistoric civilization due to their widespread distribution and a great diversity of reactions in nature. Depending on the layer structure and specific properties, such as high specific surface area, ion exchange capacity, or hydration property, clay minerals were widely used in ceramics and building materials, paper industries, oil drilling, foundry moulds, and pharmaceuticals and were also used as adsorbents, catalysts or catalyst supports, ion exchangers, and decolourizing agents [1][2][3][4][5]. ...
Handere clay deposits were discovered at Adana in Turkey. These clay units primarily consist of uncoloured claystone, pebbly sandstone, sandstone, siltstone, and mudstone marl and include gypsum lenses and clay levels of various thicknesses in places. The physicochemical properties of these clays have been investigated by different techniques including Scanning Electron and Elemental Analysis (SEM and EDS), mineralogical analyses, chemical and physical analyses, X-ray diffraction (XRD), thermogravimetric differential thermal analysis (TG-DTA), and Atterberg (Consistency) Limits Test. The mineralogical composition deduced from XRD is wide (smectite + palygorskite + illite ± feldspar ± chlorite ± quartz ± calcite ± serpentine) due to the high smectite contents (≈85%). SEM studies reveal that smectite minerals are composed of irregular platy leaves and show honeycomb pattern in the form of wavy leaves in places. The leaves presenting an array with surface edge contact are usually concentrated in the dissolution voids and fractures of volcanic glass. Organic matter content and loss on ignition analysis of raw materials are good for all the studied samples. In summary, Handere clays can be used as building materials in bricks, roof tiles, and cement and as a binder.
... Among these applications, the medical uses of clays in historical times are of particular interest. The therapeutic effects of clays have been widely recognized, and significant research performed over the recent years in the discipline of medical geology (Carretero and Lagaly, 2007;Gomes and Silva, 2007). p0010 Industrial clays are important industrial rocks with numerous industrial applications, because of their outstanding physical and chemical properties. ...
Industrial clays are very important raw materials which find numerous industrial and technological applications, including the production of materials with large added value such as nanocomposites, cosmetics, or pharmaceuticals. The versatile nature of clays is attributed to the presence of clay minerals, which impart significant physical properties to the raw materials, such as fine particle size, ion exchange, hydration and swelling, plasticity, rheological properties, colour properties, and reactions with organic and inorganic compounds. The most important industrial clays are kaolins, bentonites, sepiolite/palygorskite, and common clays and shales. Assessment of industrial clay deposits comprises determination of physical properties and direct comparison with international or regional standards or specifications dictated by the industrial end users. The latter comprise industrial specifications for particular applications. Usually, assessment includes a first general appraisal stage, in which important properties of the clay are determined, followed by a series of specific tests, which determine the suitability for certain industrial applications.
... Clays like bentonite are used in poultry nutrition for several reasons including but not limited to toxin binding (Bailey et al., 2006), improvement of the enzymatic activity in the small intestine (Xia et al., 2004) and control of ammonia into the environment (McWard and Taylor, 2000;Pappas et al., 2010). These positive results are attributed to good rheological properties, a high absorbent capacity and low or no toxicity (Carretero and Lagaly, 2007). The present study showed that chickens fed contaminated diets and bentonite performed equally well, by the end of the experimental period, compared to chickens fed uncontaminated diets. ...
The use of two bentonites differing in composition as potential binders of three mycotoxins present in broiler diets was examined with both an in vitro preliminary test and an in vivo trial. In the in vitro test, the adsorbing and desorbing ability of the two bentonites added at 1% was investigated. Concentrations of aflatoxin B1 (AFB1), ochratoxin A (OTA) and zearalenone (ZEA) were determined with LC–MS/MS and were 0.02 ppm, 0.1 ppm and 2 ppm respectively. In the in vivo trial, a total of 300 day-old, as hatched, broilers were randomly distributed in five dietary treatments with four replicate pens per treatment. In T1 treatment, broilers were fed a basal diet with neither mycotoxins nor bentonite added; in T2 broilers were fed the same diet with 1% m/m bentonite A added. In T3, broilers were fed the same diet with 1% m/m bentonite A added and three mycotoxins (AFB1, OTA and ZEA) added at levels not exceeding the EU maximum. In T4 treatment, broilers were fed the same diet with 1% m/m of bentonite B added and in T5 broilers were fed the same diet with 1% m/m of bentonite B added and mycotoxins at the same levels. Broiler performance and several biochemical and hematological parameters were examined. The in vitro test indicated a complete adsorption of 0.02 ppm AFB1 by both bentonites, present at 1%. No desorption was observed for AFB1. Adsorption and desorption of ZEA and OTA were low. The in vivo trial revealed that the overall performance of broilers did not differ between treatments. Aspartate aminotransferase was found lower in broilers fed mycotoxin contaminated diets but within normal range. The study revealed that the examined bentonites may maintain optimum broiler performance when mycotoxin levels present in the diet do not exceed EU limits and guidance values possibly by ameliorating the negative effects of other mycotoxins, not regulated by EU, present at the same time in the diet.
... Clays have been used by humanity since ancient times for manufacturing, ceramic objects, and more recently in several technological applications. Clay has also become indispensable to modern life; it is the material of many kinds of applications and they are abundant in nature, inexpensive and environmentally friendly (Bergaya et al., 2006;Carretero and Lagaly, 2007). Their structural properties can be modified by simple methods such as pillaring, to produce materials with higher surface area, porosity, thermal stability and greater capacity for adsorption and/or degradation of contaminants (Bergaya et al., 2006;Kurian et al., 2012;Tong et al., 2009). ...
... The palygorskite's cation exchange capacity ranges between 0.04 and 0.4 meq/g (Galan, 1996) usually between 0.3 and 0.4 meq/g (Murray, 2000). These properties are the reason for the palygorskite's high absorption and adsorption capacity (Carretero, 2002;Carretero and Lagaly, 2007;de Sousa Figueiredo Gomes and Pereira Silva, 2007;Viseras et al., 2007), which is the basis for many technological applications (Galan, 1996;Liu, 2007). ...
The aim of the study was to evaluate how palygorskite supplemented in broiler diets affects growth performance, mortality, litter quality and feed technological characteristics. Day-old broilers (n=192) were raised for 6weeks and fed either a corn–soybean base diet with no added palygorskite, or the same diet with 1%m/m, or 10%m/m added palygorskite. Body mass, feed conversion ratio, water intake, litter score and excreta dry matter, total and non-protein nitrogen content were assessed. To test for any negative health effects of the additive, mortality was assessed and standard hematological analyses were performed. Hardness and durability of pellets were measured to determine pellet quality. The study revealed that hardness of pellets was improved by palygorskite suggesting that it may be used as an agglomerant. Data on mortality and hematology indicated that palygorskite was safe and tolerable. The luck of statistically significant differences on improvement of litter quality with palygorskite addition could be attributed to the small scale of the study and the low stress conditions.
... Clay minerals have been widely used by human societies since the early days of mankind [1][2][3]. Modern uses of clay minerals cover a large variety of domains like building materials, ceramics, absorbents, ion exchangers, cosmetic and pharmaceutical products, oil drilling, foundry and paper industries, wastes confinement (including nuclear wastes), pollutants removal, catalysis and polymer nanocomposite reinforcement [4][5][6][7][8][9]. Clay minerals consist of a variety of phyllosilicates, commonly observed on Earth, which can be divided into several groups depending on the layer type (1:1, 2:1 or 2:1:1), charge per formula unit and nature of structural elements and interlayer species [3,10]. ...
This work describes the first hydrothermal synthesis in fluoride medium of Ni-Al montmorillonite-like phyllosilicates, in which the only metallic elements in the octahedral sheet are Ni and Al. X-ray diffraction, chemical analysis, thermogravimetric and differential thermal analysis, scanning electron microscopy and transmission electron microscopy confirm that the synthesized samples are montmorillonite-like phyllosilicates having the expected chemical composition. The specific surface areas of the samples are relatively large (>100 m(2) g(-1)) compared to naturally occurring montmorillonites. Si-29 and Al-27 nuclear magnetic resonance (NMR) indicate substitutions of Al for Si in the tetrahedral sheet. F-19 NMR and Ni K-edge extended X-ray absorption fine structure (EXAFS) local probes highlight a clustering of the metal elements and of the vacancies in the octahedral sheet of the samples. These Ni-Al phyllosilicates exhibit a higher local order than in previously synthesized Zn-Al phyllosilicates. Unlike natural montmorillonites, where the distribution of transition metal cations ensures a charge equilibrium allowing a stability of the framework, synthetic montmorillonites entail clustering and instability of lattice when the content of divalent element in the octahedral sheet exceeds ca. 20%. Synthesis of Ni-Al montmorillonite-like phyllosilicates, was successfully achieved for the first time. These new synthetic materials may find potential applications as catalysts or as materials with magnetic, optical or staining properties.
... Nowadays, clays and mineral waters are widely employed as supplementary treatments for several dermatological pathologies. Clay minerals are mainly applied in spas and specialized dermatological clinics, while the domestic market of technologically well-made geoproducts is still a rising field in the cosmetics industry (2,3). There are several applications of mineral green clays in facial dermocosmetics, and some of the most important are astringency and physical exfoliation (4), removal of impurities, dead cells and facial skin oil (5), and accumulated water drainage (4,5). ...
This article describes the optimization of a peel-off facial mask formulation. An investigation was carried out on the parameters of the formulation that most affect the desirable characteristics of peel-off facial masks. Cereal alcohol had a significant effect on the drying time at concentrations of 1-12% (w/w). The applicability of the evaluated formulations was influenced by both carbomer (0-2.4%; w/w) and polyvinyl alcohol (PVA; 2.5-17.5%; w/w) content due to their ability to alter the formulation viscosity. Inverse concentrations of carbomer and PVA led to formulations with optimum viscosity for facial application. Film-forming performance was influenced only by the PVA concentration, achieving maximum levels at concentrations of around 11% (w/w). The optimized formulation, determined mathematically, contained 13% (w/w) PVA and 10% (w/w) cereal alcohol with no addition of carbomer. This formulation provided high levels of applicability and film-forming performance, the lowest drying time possible and excellent homogeneity of the green clay particles and aloe vera before and after drying. The preliminary stability study indicated that the optimized formulation is stable under normal storage conditions. The microbiological stability evaluation indicated that the preservative was efficient in terms of avoiding microbial growth. RSM was shown to be a useful statistical tool for the determination of the behavior of different compounds and their concentrations for the responses studied, allowing the investigation of the optimum conditions for the production of green clay and aloe vera peel-off facial masks.
Properties of the chitosan films can be improved by incorporating clay minerals. So, solvent-cast films of the β-chitosan containing stevensite-rich or kaolinitic-illitic clays (up to 50 mass %) were characterized for their structural and mechanical properties. The effects of molecular weight (MW) and deacetylation degree (DD) of chitosan and the clay/chitosan mass ratio on the inhibition growth of Escherichia coli and Staphylococcus aureus were studied using the response surface methodology (RSM). The films consisted of exfoliated/intercalated or flocculated composites, and the electrostatic bonds formed between the functional moieties of the chitosan and the clay particles active sites essentially influenced their mechanical strength. The results of the study using RSM showed that the optimal value of MW required for the inhibition of the bacteria varied according to the film used, and high antibacterial activity necessitated high DD (89–97%).
A bibliometric study of the scientific production presented at the Ibero-American Congresses of Peloids (CIBAP) during the 2007-2019 period was carried out. For this purpose, the type of work, production, estimation of Lotka, subject matter of work, geographical origin and institutional origin were analyzed in the abstract books. The Universities of Vigo, Complutense of Madrid, Aveiro and Oporto are the ones that concentrate the highest percentage of scientific production. The contributions come mainly from Spain, Portugal and Argentina. The most studied topics were the thermal therapy and the physical and chemical properties of the peloids. Key words: bibliometry, mud, peloid, pelotherapy, fangotherapy, CIBAP
Recent findings highlight the role of skin microbiome in modulating immune function and inflammatory response. This systematic review aims to investigate the effects of muds, already used for the treatment of several rheumatic and dermatologic conditions, on skin microbiome. Medline via PubMed, Embase, Cochrane Library, and Google Scholar were searched for articles about the effects of therapeutic muds on microorganisms of skin microbiome. Five studies were included in the review and critically appraised. Limited data suggest that muds have various properties that may explain their action on skin microbiome, with different effects on commensal and pathogenic microorganisms. Further investigation on this topic is needed to better characterize the effects of different muds on skin microbiome, thus possibly extending their indications.
To generate effective dispersants for kaolin suspensions, it is important to study how the properties of dispersants affect their performance in suspensions. In this work, kraft lignin was modified via oxidation with nitric acid under varied conditions to produce oxidized lignin (OL) with different charge densities and molecular weights. The effects of anionic charge density and molecular weight of the lignin based products on the dispersion and sedimentation of kaolin particles were studied fundamentally. The adsorption of OLs on particles as well as the changes in the zeta potential, relative turbidity, hydrodynamic diameter and sedimentation of particles under static (non-stirring) and dynamic (stirring) conditions were systematically investigated. Dispersion studies suggested that both charge density and molecular weight had great impacts on the stability of kaolin particles. Sample OL8 with the charge density of −3.6 meq/g and molecular weight (Mw) of 30,243 g/mol was the most effective dispersant for kaolin suspension. The hydrophilicity of OLs were similar and thus did not affect the dispersion analysis.
Palladium (Pd) has been immobilized on FeCo layered double hydroxide (LDH) intercalated 10-molybdovanado phosphate (FeCo/Mo10V2-Pd) for the first time. The structure was characterized using various characterization techniques. The electrocatalytic behavior of FeCo/Mo10V2-Pd was investigated using cyclic voltammetry and linear sweep voltammetry techniques. The presence of Mo10V2 enhanced the catalytic activity of FeCo-Pd in the Heck coupling reaction. Also, the collaboration of Pd and Mo10V2 with LDH as a mesoporous support was studied. These reusable solid catalysts exhibited excellent activity, and the methodology is applicable to diverse substrates providing good to excellent yields of the desired products. This method has advantages of high yields, low reaction times, elimination of ligand and base, heterogeneous catalysts and simple methodology. It is notable that FeCo/Mo10V2-Pd can easily separate from the reaction mixture using an external magnet and reused for at least four successive runs without any considerable decrease in its catalytic activity.
Hydrotalcite-type layered Mg-Al hydroxides with Mg/Al ≥ 2 and related oxide systems have been synthesized and characterized. During the synthesis of the Mg-Al hydroxides with Mg/Al = 2 and 3, the interplanar spacings decrease because of the replacement of the interlayer NO3- anion by the CO32- anion. Morphologically, the initial materials are aggregates of ∼1-μm oblong planar particles with a layered structure. The transverse dimension of the plates is 50-100 nm, and their thickness is 10-30 nm. As a rule, these planar particles are heavily distorted. Heat treatment of the Mg-Al hydroxides in the temperature range from 450 to 600°C causes the separation of the layered structures into planar domains of epitaxial MgAl2O4/MgO structures, which survive heat treatment at 900°C. During this heat treatment at 900°C, the greater part of the sample breaks down into two-dimensional particles of defective MgO and MgAl2O4 phases whose size is up to 100 nm. The oxide compositions synthesized from the layered Mg-Al hydroxides have a large pore volume and a fairly high specific surface area, which are retained upon heat treatment at 1000-1100°C.
Based on the author's lectures to graduate students of geosciences, physics, chemistry and materials science, this didactic handbook covers basic aspects of ceramics such as composition and structure as well as such advanced topics as achieving specific functionalities by choosing the right materials. The focus lies on the thermal transformation processes of natural raw materials to arrive at traditional structural ceramics and on the general physical principles of advanced functional ceramics. The book thus provides practice-oriented information to readers in research, development and engineering on how to understand, make and improve ceramics and derived products, while also serving as a rapid reference for the practitioner. The choice of topics and style of presentation make it equally useful for chemists, materials scientists, engineers and mineralogists.
The study aimed to investigate the effect of feed palygorskite inclusion on pelleting technological characteristics, growth performance and tissue trace elements content of blunt snout bream, Megalobrama amblycephala. Diets without (control group) or with 2% palygorskite were pelleted and were measured for pelleting technological characteristics. Then the diets were fed to two groups of fish in four replicates (30 fish per replicate) for six weeks. Compared with the control group, dietary 2% palygorskite inclusion enhanced pellet production rate, pellet durability and the degree of starch gelatinization of pellet, and reduced percentage of fines. There was no difference in the weight gain, feed conversion rate, condition factor, hepatosomatic index and viscera/body ratio of fish between groups. Palygorskite supplementation significantly enhanced the Fe content in the blood and muscle and Zn content in the muscle, but reduced muscular Cd concentration. However, the accumulations of Cu and Pb in the body were not affected by palygorskite. The results indicated that dietary palygorskite supplementation could enhance pellet production efficiency, pellet quality, and alter trace elements accumulation in the tissues without impairing growth performance of blunt snout bream.
New medical clay/polyvinyl alcohol nanocomposites of similar composition were prepared by both solution intercalation and mechanical mixing. Thermal and structural characterization of the precursors and of the composites showed that under proper parameters of mixing/milling process the composite can achieve structural properties to a large extent similar to that of the composite obtained by solution intercalation. In both cases of clay-polymer nanocomposites the clay occurs preponderantly as separated phase.
Molybdate inserted layered double hydroxides (LDHs) were prepared by anion exchange in their aging step of synthesis under hydrothermal conditions. These materials were characterized by X-ray diffraction, chemical analysis, N2 physisorption, DR UV–vis and Raman spectroscopy. The solids as prepared showed interesting chemical, structural and textural properties. They proved high catalytic activity for the oxidation of sulfur-containing organic molecules and anthracene by hydrogen peroxide under gentle reaction conditions. The results were compared to those obtained over Mo-containing LDHs prepared by conventional ion exchange.
The varied mineralogical composition of earthy materials and the quantity of elements extracted by simulated stomach acid substantiate the diversity of materials consumed by humans practicing geophagy. Direct consumption of 'edible earths' for medicinal and spiritual purposes occurs worldwide and is deeply rooted in 'folk medicine' and religion. The legends associated with the healing powers of the clay from Chimayo, New Mexico, provide an excellent example of the roots of geophagy. The clay mineral assemblages revealed by X-ray diffraction analysis of 22 samples from New Mexico, North America, and other parts of the world are highly variable. One might be monominerallic kaolinite or smectite, and another, a complex mixture of illite, kaolinite, smectite, and chlorite or vermiculite. The quantities of elements (Al, Si, K, Na, Ca, Mg, Fe, Mn, Ti, P, S, Ba, Sr, Pb, Zn, Cd, Co, Cu, Cr, Ni, V, Zr, Se, Mo, Be, Sb, and As) extracted by 0.12 M HCl varied from ∼1.0 mg/g to the limit of detectability, 0.0001 mg/g. Potential long-term human health effects were evaluated with the Reference Dose Ratio (RDR). It divides the quantity of the element extracted from 50 g of the total sample by the recommended reference dose (RfD) reported in the Environmental Protection Agency's (EPA, USA) IRIS (Integrated Risk Information System) database. Median RDR values for Na, Cr, Sb, and As exceeded 1.0 indicating an abnormally high potential intake. Materials consumed by humans are so varied that caution should be used in comparing the results of one clay study with those of another without mineralogical and chemical data.
This review is focused on the preparation and potential applications of hydrotalcite like compounds organically modified by ion-exchange procedure and the data reviewed have been supplemented with unpublished results. It is divided in two Parts. Part I deals with intercalation of biologically active species such as amino-acids, anti-inflammatory and antibiotic drugs, UV-absorbers to produce nano-hybrids with versatile application as biomolecule reservoir and in the pharmaceutical and personal care fields. Part II deals with the intercalation of several anions with either hydrophobic or hydrophilic properties in order to make the inorganic sheets compatible with different polymers. Moreover, if the guest is an active molecular anion such as antimicrobial, antioxidant, antibiotic or anti-inflammatory, the polymer can acquire the peculiar properties of the guest opening novel interesting application fields.
The review paper has briefly summarized the development of the use of layered double hydroxides (LDHs) and their derivatives as heterogeneous and recyclable catalysts/catalyst supports for various reactions in the period of 2005 to early 2010. The catalysis reactions involve a number of important fields, such as organic/pharmaceutical synthesis (e.g. the formation of several types of organic bonds), clean energy (e.g. the production of hydrogen and popular carbon nanotubes), and environmental pollution control (e.g. total decomposition of volatile organic compounds, photodecomposition of organic wastes, DeNOx and DeSOx). The authors have also commented on the state of the art of research and pointed out the potential future directions in developing LDH-based catalysts. This review has thus indicated that LDH-based catalysts are important materials useful in these fields and it is worthwhile making more efforts towards the development of LDH-based catalysts.
INTRODUCTION: It is estimated that five to ten percent of the 6.2 million fractures occurring annually in the United States result in delayed or impaired healing. Osteoinductive agents are a possible avenue to augment surgical procedures or treat the plethora of standard fractures. A great challenge presented in the science of biological bone growth factors at this time seems to be developing the best delivery mechanism and kinetic. Direct injection or oral applications do not present appropriate remedy, but the controlled localized delivery of osteoinductive therapeutics from polymeric biodegradable implants is a valid alternative. We have demonstrated a marked capacity of IGF I to bridge non-union defects, when delivered in a controlled localized fashion1,2. We report the impact of release kinetics and polymer choice on new bone formation within sheep fracture models and concomitant changes in the expression of various marker genes relevant for bone formation, resorption, and turnover. METHODS: IGF I was encapsulated in various types of poly (lactide-co-glycolide) (PLGA 502H, 502, 503H, 752) and poly-lactide (PLA 202) microspheres (MS) using solvent evaporation (loading 0,1%). IGF I in vitro release kinetics from the microspheres were monitored for 72 days by radioimmunoassay (RIA) analysis. The in vivo study was performed in 6 sheeps in an 8 mm drill hole defect model (8 defects per animal). Each defect received either (i) 100 mg unloaded microspheres or (ii) 100 mg MS loaded with 100 µg IGF I (IGF I-MS) or (iii) were left unfilled (negative control). Three animals were sacrificed after 3 weeks and another three 6 weeks post operation. The bones were cut, and slices prepared for histology (acrylic resin embedding, grinding and thin sections were stained with toluidine blue/von Kossa) and for RNA extraction3. Upon reverse transcription, the gene expression of pro - and inflammatory proteins (interleukins 1α and 6, cyclooxygenase 2), inducible NO synthetase, and morphogeneic factors (platelet derived growth factor A, transforming growth factor β 1, fibroblast growth factor, IGF I) was analysed by real-time polymerase chain reaction.
Clay is used for cosmetic and medicinal purposes for thousands of years because of well known clay properties. Analysis about commercial cosmetic clay products available on Latvia market is done by gathering information about manufacturer country, clay color, product type and price. Mineral and granulometric composition of some cosmetic clay were determined by X-Ray diffraction analysis (XRD) and laser diffraction method. The study evaluates Latvian clay suitability for cosmetic purposes.
Data analysis of cosmetic clay available on the market showed that product types range from facial masks to shampoos. On cosmetic product packages clay color is stated twice more often than a specific clay mineral. In traditional medicine clay therapeutic properties are classified by clay colour. There are no data in scientific literature about clay color effect on therapeutic properties.
XRD analysis of 12 clay containing products without additives showed that products contain variety of clay minerals (illite, smectite, kaolinite, illite/smectite, chlorite) and quartz. XRD analysis demonstrated that information about mineral composition on clay cosmetic products is partially incomplete. All samples contained illite which is the most abundant clay mineral in Latvia. Particle size distribution of analyzed
cosmetic clay are broad monomodal. Clay fraction amount in commercial cosmetic clay varies between 25 till 54%.
Comparision of literature data and data obtained in this study on mineral and granulometric compositions of cosmetic clay and Latvian clay showed that Latvian clay is suitable for cosmetic and medicinal purposes. For complete characterization of Latvian clay usage in cosmetic further studies are needed.
Kosmētiskiem un ārstnieciskiem mērķiem mālus izmanto jau vairākus tūkstošus gadu to daudzveidīgo īpašību dēļ. Pētījumā apkopoti jaunākie literatūras dati par mālu lietojumu šajās nozarēs. Apskatot Latvijas patērētājam pieejamo mālus saturošo kosmētisko produktu piedāvājumu, ir apkopota informācija par produktu izcelsmes valstīm, uz iepakojuma norādīto sastāvu, krāsu, produkta veidu un cenu, kā arī eksperimentāli analizēts to minerālais un granulometriskais sastāvs. Minerālā un granulometriskā sastāva noteikšana veikta ar rentgenstaru difrakcijas analīzes (RDA) un lāzera granulometrijas metodēm. Pētījumā novērtēta Latvijas mālu piemērotība pielietojumam kosmētikā. Atslēgas vārdi: kosmētiskie māli, minerālais sastāvs, granulometriskais sastāvs.
A nanostructured hydrotalcite-like compound of formula [Zn0.72Al0.28(OH)2] Br0.28·0.69 H2O has been used as inorganic layered host of the anionic form of diclofenac (DIK), a Non Steroidal Antiinflammatory Drug. The obtained intercalation compound has been characterized by chemical analysis, X-ray powder diffraction pattern, thermogravimetrical analysis and SEM and TEM microscopy. The nanohybrid ZnAl-DIK, with empirical formula [Zn0.72Al0.28(OH)2]DIK0.281.35 H2O and interlayer spacing 22.5 Å, was made up of submicrometric hexagonal platelets. The drug loading was 41.8% w/w. The material was submitted to in vitro drug release studies using three different simulated intestinal media. The release profiles were fitted by mathematical models describing various kinetics in order to investigate the drug release mechanism. The results were compared to literature data obtained with micro-sized MgAl-DIK.Graphical abstractResearch Highlights►Diclofenac has been intercalated into a nanostructured ZnAl-HTlc. ►ZnAl-DIK was submitted to in vitro drug release studies. ►Drug release was complete at pH 7.5 and incomplete in different media at pH 7.0. ►The diffusion of DIK through nanosized ZnAl is faster than that through micro-HTlc.
This review treats with recent patents and related literature, mainly from the Authors laboratories, on biomedical and food packaging applications of nano-composites constituted of biodegradable polymers filled with micro or nano crystals of organically modified Layered Double Hydroxides of Hydrotalcite type. After a brief outline of the chemical and structural aspects of Hydrotalcite-like compounds (HTlc) and of their manipulation via intercalation of functional molecular anions to obtain materials for numerous, sometime unexpected applications, the review approaches the theme in three separated parts. Part 1 deals with the synthetic method used to prepare the pristine Mg-Al and Zn-Al HTlc and with the procedures of their functionalization with anti-inflammatory (diclofenac), antibacterial (chloramphenicol hemisuccinate), antifibrinolytic (tranexamic acid) drugs and with benzoates with antimicrobial activity. Procedures used to form (nano) composites of polycaprolactone, used as an example of biodegradable polymer, and functionalized HTlc are also reported. Part 2 discusses a patent and related papers on the preparation and biomedical use of a controlled delivery system of the above mentioned pharmacologically active substances. After an introduction dealing with the recent progress in the field of local drug delivery systems, the chemical and structural aspects of the patented system constituted of a biodegradable polymer and HTlc loaded with the active substances will be presented together with an extensive discussion of the drug release in physiological medium. Part 3 deals with a recent patent and related papers on chemical, structural and release property of antimicrobial species of polymeric films containing antimicrobial loaded HTlc able to act as active packaging for food products prolonging their shelf life.
Colloidal aqueous dispersions of nanometric NiAl, ZnAl, NiCr, ZnCr, NiFe, and MgFe hydrotalcite-like compounds were prepared in a water/cetyltrimethylammonium bromide/n-butanol/isooctane microemulsion. Particle sizes were analyzed with different techniques, and the results confirm dimensions between 10 and 30 nm, except for ZnAl-HTlc (150-200 nm). A good colloidal stability of HTlc-NPs aqueous dispersions, investigated with DLS and Pz measurements, was obtained without the need for any stabilizing agent. SEM images clearly showed that the obtained HTlc posses a high tendency to spontaneously form homogeneous and dense stacking of plate-like HTlc crystals directly from aqueous solution, giving rise to the developing of functional materials in optical, electrical and magnetic fields.
This chapter describes clay-based formulations of pesticides, whose design was to solve environmental and economical problems. The chapter focuses on herbicides—the leading type of pesticide used. Herbicides are applied to fields to impede the growth of weeds. However, only a part of the applied amount is bioactive, a certain part remains attached to the soil and another part is leached out and migrates into ground water or undergoes surface migration. Thus, application of herbicides to the field causes serious water contamination, and can hurt neighboring crops. This problem is particularly serious with hydrophobic herbicides (acetochlor) and anionic herbicides (sulfometuron). Leaching of the herbicide requires higher amounts of the herbicides to be applied, which also enhances environmental problems. As production and uses of herbicides are increasing, the serious health and environmental problems posed by these toxic compounds must be controlled to minimize the harmful effects of these products.
Aflatoxins are toxic compounds found in grains and other food crops infested by Aspergillus fungi. Aflatoxins B1 and M1 are recognized carcinogens for animals and humans. Clay additives have been used to pelletize and improve the flow characteristics of animal feeds. Reduced aflatoxicosis in animals is an extra benefit of clay additives. Clay additive use has also been examined for reducing human aflatoxicosis. In this study, aflatoxin B1 (AfB1) adsorption by reference clays and activated carbon (AC) will be compared to a commercial clay additive, Novasil, that lessens aflatoxicosis in animals. The n-alkylammonium expansion identified Novasil as a low-charge montmorillonite. AC and the montmorillonites, Novasil, SWy-2, and SAz-1 adsorbed ∼ 200 g/kg AfB1 from water, whereas, sepiolite (SepSp-1) adsorbed only ∼ 60 g/kg. For AfB1 adsorption from aqueous corn meal, a 60% methanol extraction was used. Retention of AfB1 from corn meal by all samples was much less (< 1.5 g/kg) than from water and suggests that methanol might remove weakly-adsorbed AfB1. Low-charge montmorillonites, Novasil and SWy-2, retained ∼ 0.7 g AfB1/kg from corn meal, but high-charge montmorillonite (SAz-1) and AC only retained ∼ 0.1 g/kg. SepSp-1 adsorbed less AfB1 from water than AC or montmorillonite, but retained more AfB1 (1.3 g/kg) from corn meal at a lower equilibrium concentration. A plot of AfB1 extracted from corn meal versus % clay suggests SepSp-1 is far more effective than the montmorillonites. Methanol extraction is a more cautious estimate of AfB1 binding than simple aqueous adsorption and might better correlate to reduced aflatoxicosis in animals and humans.
The lake sediments display a typical upper crustal composition and include a less fractionated component related to the closely exposed Cambrian continental arc. No basic source component could be detected. The sediments are strongly chemically weathered (K/Cs < 2000; CIA 70–80) and depleted in most of the major and trace elements. The depositional environment is characterised by oxidising conditions regarding geochemical constraints and facies conditions. Only U (5–15 ppm), W (9–21 ppm) and As (5–22 ppm) are strongly enriched trace elements related to the post-Archaean average Australian shale or upper crust. This enrichment is explained as related to mining activities and mineralisation. W and U mines are common in closest vicinities. The enrichment in U does not reflect the concentrations in the mined bodies, thus, the loss of U during transport and sedimentation was most probably buffered by sediments deposited under anoxic conditions and/or plants. Those trace metal element traps may contain much higher element abundances as the sediments here discussed.This preliminary study conducted with simple, quick but effective methodology shows alarming concentrations of trace metals in sediments, although the selected sediments are not the most likely to concentrate elements like U. This implies that suitable sediments and sedimentation areas have to be determined carefully by comprehensive fieldwork and guided by the understanding of the local drainage systems. If this is ignored, a reliable study, which excludes contamination, cannot be conducted. Based on our preliminary studies, the water, sediments and flora should not be used for human purposes until contamination sources and flux is entirely understood, which is not the case for this highly contaminated zone so far.
The combination of erythromycin and zinc in the topical antibiotic therapy of acne has been proved useful to reduce the development of antibiotic-resistant strains. An Italian zeolite-rich rock, containing 66<sup> </sup>wt.% of clinoptilolite, has been used to prepare an active carrier for erythromycin. The zeolite has been conditioned in zinc form by a set of cation exchange processes, then erythromycin has been adsorbed onto the micronized rock by vacuum drying. After 6<sup> </sup>month ageing, almost 95% of the loaded drug was found, indicating good stability of the Zn-carrier-erythromycin system. Minimum inhibitory concentration (M.I.C.) assay on Propionibacterium acnes showed that the process of adsorption of erythromycin does not affect its antimicrobial activity. Both drug and zinc release were evaluated from the carrier powder: the erythromycin release was more than 80% in the first hour and independent on hydrodynamic conditions (United States Pharmacopoeia dissolution apparatus or Franz cell). The release of zinc was fast, and more dependent on the hydrodynamic conditions. The influence of formulating the carrier by dispersion in two anhydrous bases, an absorption petrolatum base (HP) and a water soluble polyethylenglycol base (PEG), was evaluated. In both cases erythromycin and zinc showed a release quantitatively similar to that of the powder, although the release rate was slightly lower from the more hydrophobic HP base.
Chief events and changes in philosophy or science from the 16th to the 20th centuries preceding the beginnings of clay science are summarized in three tabular surveys. In a further tabular summary, it is shown that clay science or argillology emerged in the mid-20th-century after many pioneering discoveries and intensive activities. It has been established as an autonomous science connected with mineralogy and related inorganic but also organic disciplines of natural sciences and technology. From this time, its evolution has been supported by the development of new powerful methods and a broad interdisciplinary cooperation. Clay science at the end of the 20th century covers six big research regions: 1) crystal structures (including chemistry); 2) research methods; 3) natural accumulations and genetic conditions of clay and related minerals; 4) physical and physicochemical properties; 5) modified clays; 6) clay science oriented to the exploitation and beneficiation of the raw materials and the application. Each research region is divided into several subregions. The evolution of clay science is illustrated on parts of two fundamental research regions: 1) crystal structures (including chemistry) of a) clay mineral species and their groups, and of b) mixed-layer structures and their transformations; 2) research methods. The present trends and next future of clay science can be seen as a continuation in the six big research regions going into greater depth and breadth.
Clays are one of the more important industrial minerals. Clays are comprised largely of clay minerals and have applications in many facets of today's society including agriculture, geology, construction, engineering, process industries, and protecting the environment. Research and development by clay scientists in academia, government, and industry contribute to our fundamental understanding of these extremely small particle size minerals. This research and development results in new, innovative, and improved clay products. It is important to understand that a fundamental knowledge of the structure and composition of clay minerals - kaolins, smectites, palygorskite-sepiolite, illite, and chlorite - is necessary to develop industrial applications. The various clay minerals have major and minor differences in their physical and chemical properties which are related to their structure and composition. These structural and compositional attributes of clay minerals are correlated with their physical and chemical properties in this paper. The correlation between the properties and the structure and composition explains why kaolinite is an excellent paper coating material and a necessary component in many ceramic, products; why sodium montmorillonite is a major ingredient in drilling muds; why calcium montmorillonite is an excellent sorbent clay; and why palygorskite is a superior gelling clay in sys_tems with high contents of electrolytes and salts. Other applications related to the structure, composition, and physical and chemical properties of clay minerals are described. Processing techniques and some new and improved products that have recently been developed are also described. As our fundamental knowledge concerning clay minerals increases, they will become even more important industrially and scientifically.
The modern days of clays are characterized by changes of mineral policy. Goals and strategies are refined and the applied clay science is formulated. Clay research is focused on four major fields: (a) soils and agriculture; (b) industrial applications; (c) engineering and geotechnics; and (d) research and development of new products.A general shift from the empiric to the exact approach in clay research is in progress. New applications of clays and new products from clays are expected to emerge. Instead of a long list of clay applications in different industries, several crucial aspects of the future development are discussed in the following paragraphs.
The main commercially important kaolin resources are the primary deposits in Cornwall, UK, and the sedimentary deposits in South Carolina and Georgia, USA. Annual world production is approx 18 Mt. The extraction and production of kaolins are described for both primary and sedimentary deposits. The main use of kaolin is as a paper filler and a paper coating pigment. The various filler and coating grades are indicated, and the effect of kaolin properties on coated sheet properties is discussed. Kaolin is a major component in most ceramic bodies. Examples of formulations are given. The manufacture of sanitaryware and tableware is discussed in terms of kaolin properties. Kaolin is used as an extender in aqueous based paints and as a filler in rubber and synthetic polymers. The surface chemical properties of kaolin have been widely researched. There is no uniform view on the origin of the cation exchange capacity. Aqueous suspensions of kaolin are flocculated at low pH. The deflocculation of kaolin under alkaline conditions is important, and is assisted by adding a polyanion. The Kubelka-Munk equations have provided a useful basis for interpreting optical properties of kaolins in terms of an absorption coefficient (k) and a scattering coefficient (s). The k is a bulk property, interpreted in terms of light absorption by ancillary minerals, by coatings of hydrated iron oxides on the kaolinite particles and by transition metals in the kaolinite structure. The s depends on the size distribution of the platelets and the manner in which they are packed together. The rheological properties of deflocculated suspensions of kaolin in water are important in modern paper coating applications. The relation between the bulk physical properties of kaolin and rheology is complex. Viscosity at low rates of shear increases with increasing specific surface area of the kaolin. Viscosity at high rates of shear depends on the shapes of the particles and their packing. -D.J.M.
This chapter describes layered double hydroxides. Among the group of minerals referred to as nonsilicate oxides and hydroxides, the layered double hydroxides (LDH) have many physical and chemical properties that are surprisingly similar to those of clay minerals. Their layered structure, wide chemical compositions (because of variable isomorphous substitution of metallic cations), variable layer charge density, ion-exchange properties, reactive interlayer space, swelling in water, and rheological and colloidal properties make LDH clay-like. However, because of their anion-exchange properties, LDH were referred to as “anionic clays.” Most metals in the first transition series can be incorporated into the hydroxyl sheet of the hydrotalcite-like structure. Thus, the formation of mixed metal-Al secondary precipitates may be a general reaction mechanism for transition metal adsorption to clay minerals.
This chapter describes the beneficial and harmful effects of clay mineral. Clay minerals can be beneficial to human health by serving as active principles or excipients in pharmaceutical preparations, in spas, and in beauty therapy medicine. In some cases, however, these minerals may be harmful to human health. In pharmaceutical formulations, spas and beauty therapy, clay minerals are used for therapeutic purposes and their beneficial effect on human health. In pharmaceutical formulations, these minerals are used as active principles (gastrointestinal protectors, antacids antidiarrhoeaics, dermatological protectors, cosmetics) and excipients (inert bases, delivery systems, lubricants, emulsifiers). In spas and beauty therapy, clay minerals are used in geotherapy, pelotherapy, and paramuds to treat dermatological diseases, alleviate the pain of chronic rheumatic inflammations, moisturize the skin, and combat compact lipodystrophies and cellulite. However, clay minerals can also have an adverse effect on human health when they are inhaled over a very long period. In the lung, clay minerals can cause diverse pathologies such as cancer, mesothelioma, or pneumoconiosis, but the toxicity of these minerals is generally related to the presence of quartz or asbestos from mining operations. The pathogenicity of fibrous clay minerals (sepiolite and palygorskite) is related to the geological conditions of formation.
The clay minerals kaolin, smectite and palygorskite-sepiolite are among the world's most important and useful industrial minerals. Clay minerals are important in a number of geological applications such as stratigraphic correlations, indicators of environments of deposition and temperature for generation of hydrocarbons. In agriculture, the clay minerals are a major component of soils and determinant of soil properties. The clay minerals are important in construction where they are a major constituent in brick and tile. The physical and chemical properties of the clay minerals determine their utilization in the process industries.
What about tomorrow? Processing techniques will be improved and new equipment will be available so that improved clay mineral products will be available. Pillared clays and nanocomposites will become important. Further developments in organoclay technology and surface treatments will provide new usages for these special clays. Tomorrow will see further growth and utilization of the clay minerals.
The mineralogy and occurrence of an Iranian clay size deposit, locally called ‘Gel-E-Sarshour'’ or shampoo-clay, was studied. The material is mined from shallow subsurface channels of 25 to 50 m in length which occur on hilly landforms of limestone outcrops associated with the Cretaceous Jahrom Formation in S-Iran. Clay masses (1 to 2 m thick) inside caves are wet and plastic with dominantly gray colors and sandwiched between two layers, of dense dolomitic limestone. The clay is extremely hard with a soapy feeling upon dehydration.After wetting and mixing with some rose water for the purpose of fragrance, the substance is mainly used as a shampoo (to combat dandruff and excessive greasiness) because of its swelling property, high specific surface and absorption capacity (especially Mg). The powdered form is used for treatment of burns, rashes, and also as a deodorant, poison absorbent and soil conditioner. Upon hydration, it forms gel-like masses and swells in excess of its original volume.The mineralogy of the Zarrin-Mine bentonite, which is mined in Iran and used by oil companies, was also studied as a reference.The study carried out by XRD, IR and chemical analysis has shown that the main component of the Gel-E-Sarshour clay is a dioctahedral smectite of high layer charge, with minor amounts of mica, vermiculite and quartz.
Clays have been and continue to be one of the more important industrial minerals. Clays and clay minerals are widely utilized in many facets of our society. They are important in geology, agriculture, construction, engineering, process industries, and environmental applications. Traditional applications are many. Some of the more important include ceramics, paper, paint, plastics, drilling fluids, foundry bondants, chemical carriers, liquid barriers, decolorization, and catalysis.Research and development activities by clay scientists in academia, government, and industry are continually resulting in new and innovative clay products Many of these new applications are the result of improved processing, which provides clays of higher purity, more precise particle size and distribution, whiter and brighter color, modified surface chemistry, and other physical and chemical modifications. Some new and improved clay products include tailored or engineered paper coating kaolins, enhanced paint thickeners, nanocomposites for plastics, pillared clays as special absorbents and catalysts, clays for liquid fertilizer suspensions, clays for absorption of animal wastes, calcined kaolins with high brightness and low abrasion, faster casting clays, and clays with a very high modulus of rupture.Improvement of mining and processing techniques will lead to the continued growth of traditional clay applications and to the development of new and innovative clay products. Value added products are the wave of the future for the traditional industrial clay minerals.
The structure, chemical composition, exchangeable ion type and small crystal size of smectites are responsible for several unique properties, including a large chemically active surface, a high cation-exchange capacity, interlamellar surfaces having unusual hydration characteristics, and sometimes the ability to modify strongly the flow behaviour of liquids. In terms of major industrial and chemical uses, natural smectite clays can be divided into three categories: Na-smectites, Ca,Mg-smectites and Fuller's or acid earths. Large volumes of Na-smectites and Na-exchanged Ca,Mg-smectites and Fuller's earth are directly used in the foundry, oil well drilling, wine, and iron ore and feed pelletizing industries, and are also used in civil engineering to impede water movement. Significant volumes of Na-smectites are used for various purposes in the manufacturing of many industrial, chemical and consumer products. Large quantities of Ca,Mg-smectites are used directly in iron foundries, in the agricultural industry and for filtering and decolorising various types of oils. A significant fraction of the Ca,Mg-smectites used for decolourizing has been acid treated. Large volumes of Fuller's or acid earths are commercially used for preparing animal litter trays and oil and grease absorbents, as carriers for insecticides and for decolorising of oils and fats. Natural Na-smectites occur in commercial quantities in only a few places, but Ca,Mg-smectite and Fuller's earth deposits of considerable size occur on almost every continent.-D.J.M.
This chapter discusses the applications of clays and clay materials for pollution control. Because of the ubiquitous and widespread occurrence of clays in soils and sediments, clays are long used for the control of toxic materials albeit at a small scale or only locally—for example, Lemnian earth was used medicinally in ancient Greece and Turkey to counter the effects of snakebites and poisons and to cure festering wounds. The undoubted usefulness of clays for pollution control and environmental protection arises from many of the same characteristics that made them so useful industrially and otherwise in human societies for many centuries. The chapter provides some of the particular or proposed applications of clays for pollution control and environmental protection, delineates properties of clays that make them useful for these applications, and outlines the requirements for pre-treatment that enhance their effectiveness in each case.
The term “priority pollutants” is used to define chemicals hazardous to aquatic life or human health. Thus, it is essential to remove such pollutants from water and try to reduce their impact. Clay minerals might be helpful in the removal of hazardous chemicals, due to impressive adsorption properties. Natural clay minerals adsorb cations and non-charged hydrophilic compounds, but almost do not interact with anions and hydrophobic pollutants as most organic pollutants, including naphthalene and phenolic derivatives. By pre-treating clay minerals with a suitable organic cation, the surface properties of the adsorbent may be adapted, and fast sorption is observed, removing large amounts of such pollutants. In this study we present efficient sorption of naphthalene and several phenolic derivatives to organoclays prepared by adsorption of crystal violet or tetraphenylphosphonium ions on montmorillonite, until a charged-neutralized surface is obtained. The amounts of pollutant adsorbed are at least of the same order of magnitude of those measured for high quality activated carbon, but the adsorption proceeds almost immediately, whereas for activated carbon it takes tens of minutes. The proposed organoclays were mixed with sand and tested in column filters, showing complete removal of high concentration of pollutant at several pore volumes. The adsorbents can also efficiently be applied in “sequential batch” reactors due to the fast adsorption kinetic, followed by flocculation that allows easy separation of the purified effluent. A volume of 150 ml of a 1000 μM TCP solution was completely purified to levels below 3 μM, by means of 0.25 g organoclay.
This chapter discusses the applications of clays and clay materials as drugs. Clay minerals are efficient against several aggressors that cause major disorders of the gut. These beneficial effects of clay minerals (on the gastrointestinal mucosa) are associated with two mechanisms of action: (1) adsorption of the aggressors or their toxic secretions and (2) modification of the thickness and rheological properties of the adherent mucus, reinforcing the natural defenses of the gastrointestinal mucosa. At the surface of the gut, a mucus gel adheres to the epithelial cells of the mucosa. This adherent mucus is dynamic, being continuously secreted by the calceiform cells and regularly eroded by environmental aggressors present in the gut lumen. The mucus gel is largely composed of glycoprotein polymers, lipids, and proteins linked together by covalent bonds. It acts as a physical barrier protecting the mucosa against penetration by extraneous molecules and mechanical injury. By maintaining a pH gradient and competing with the epithelial surface for microorganisms, the mucus gel also acts as a chemical barrier.
The need for kaolin pigments by the paper industry with controlled optical and physical properties have significantly changed the type of filler and coating clays available to the paper industry. Processing equipment now used in the production of kaolin products is much more sophisticated and controllable than in the past. Better understanding of the mineralogy and the physical and chemical properties of kaolins, in addition to improved processing techniques, has allowed the kaolin processors to produce engineered or tailored grades that meet particular needs of the user. Particle size and shape, brightness, gloss, opacity, and viscosity can be altered and controlled to meet specific requirements of the paper coater. Examples of several types of engineered products available for use by the paper industry are discussed.
Two different bentonites (saponite and montmorillonite) have been used for maturation with seawater. These bentonites are very rich in phyllosilicates (> 90%), with calcite, silica minerals (quartz, cristobalite) and feldspars (plagioclase) as subordinated minerals. Maduration tests have been realized both in static and stirring conditions and sampling points at 0, 15, 30, 60, 90 and 120 days have been established. Several mineralogical (XRD, SEM-EDX) chemical and physico-chemical (CEC, pH, granulometry, plasticity, conductivity) analytical techniques have been used. Results indicate no mineralogical changes during maturation process but differences in the smectite crystallinity (crystallite size) and basal spacing d(001). The last related with the variation of exchangeable cations (mainly Na+ for Ca2+) within the smectite interlayer. Variations in granulometry, plasticity index and conductivity have also been observed. Similar results are reported for static and stirring procedures, and therefore the former is preferred. Maturation time of between 60 and 90 days would be enough for the bentonite to achieve the optimum physico-chemical properties for its use as a peloid. Between the two bentonites under study, saponite is clearly better than montmorillonite for its application as peloids in pelotherapy. This fact is mainly due to differences in grain size distribution and consequently in the cationic exchange capacity, which enables in saponite a higher retention of water ions making possible their transference to patients, and therefore reaching a better influence in their health.
The thermal behaviour of muds and clays for pelotherapic purposes is a very important parameter because its directly relation with the therapeutic action of peloids. Usually common clays are used for maduration in pelotherapy but rarely are used pure clays as bentonites or sepiolite. Under study in this work are the thermal properties of almost pure samples of Al-bentonite (montmorillonite), Mg-bentonite (saponite) and sepiolite, and their comparison with three common clays composed of mixtures of kaolinite, illite and smectite with other silicates and carbonates. The samples have been characterized by means of mineralogical techniques (XRD) but also by chemical analysis (XRF, AA), microfabric studies (SEM) and physical and physico-chemical determinations (granulometry, BET surface area, plasticity index, water absorption and CEC). Results indicate noteworthy differences between common clays and pure clays, especially with Mg-bentonite. Besides water absorption capacity other physical and physico-chemical properties seem to play an important role in the cooling kinetic and therefore in the selection of candidate clays for pelotherapy.
Pelotherapy is the application of thermal muds (“peloids”) for recovering muscle–bone–skin pathologies; more recently such old practice has received applications also for wellness and relax purposes.Thermal muds are hydrothermal or hydrothermalized pastes produced by primary or secondary mixing of clayey (geo)materials with salty thermo-mineral waters, accompanied by organic materials produced by the biological-metabolic activity of micro-organisms growing during the so-called “maturation” process.Many spa-centres have been using peloids occurring in-situ, but natural reserves are going exhausted; therefore, thermal muds are currently prepared by maturation of tailored clayey raw (“virgin”) materials mixed with salty thermo-mineral waters gushing out in-situ.Various factors are ruling the quality of a peloid: virgin clay, thermo-mineral water and maturation procedure.Nowadays pelotherapy is being more-and-more focused on specific pathologies and treatments; such innovative health applications need a “certification” of the peloids suitability. Worse applications of thermal mud could produce non-beneficial effects, or cause relapse.It is suggested to set up a Network of specialized laboratories for the certification after standard criteria of the quality and suitability of peloid muds, and to appoint an European Master. Degree for assisting the physicians in selecting the peloids in view of treatments focused on different pathologies.
The work deals the interactions between two commercial clays, a bentonite and a kaolin, and an iron-salicylate complex. Adsorption experiments were accomplished using a water solution containing Fe(III) 0.0176 M and salicylic acid 0.0253 M. Natural and treated clay samples were characterized by chemical analyses, powder X-ray diffraction, thermal analyses. The time dependence of salicylic acid adsorption by bentonite follows first-order kinetics, with respect to the percentage of salicylic acid adsorbed. in the first 12 h; afterwards the reaction slows down. The reaction is completely exhausted after 2 days and during the next 4 days the concentration of salicylic acid in bentonite does not change from its asymptotic value of 8.0%. The adsorption kinetics of salicylic acid by kaolin highlights a slow adsorption beginning after the fourth day of treatment, and finished after 19 days. The amount of salicylic acid adsorbed was 5.5% of the final complex. The release of salicylic acid adsorbed by bentonite and kaolin was tested in 0.2 N solutions of Na(+), K(+), Mg(2+), and Ca(2+). Salicylic acid release rates from Fe(III)-salicylate-containing bentonite were also measured through cellulose acetate membranes by means of Franz-type diffusion cells: an initial slow release of salicylic acid was followed by a fast release phase; after 23 h the concentration of salicylic acid released can be considered constant and the drug desorbed was 1.4% of the amount adsorbed by the bentonite. Even if the desorbed amount of salicylic acid is not very high, the bentonite-salicylate complex could be suitable for an application by gradual release. (c) 2006 Elsevier B.V. All fights reserved.
Layered double hydroxides with Mg and Al cations in the layers (Mg/Al molar ratio 2) and with intercalated mefenamic and meclofenamic acid anions have been prepared by coprecipitation, ion exchange and reconstruction. The solids have been characterized by X-ray diffraction, FTIR spectroscopy and assessment of specific surface area; their thermal stability has been studied by differential thermal and thermogravimetric analyses. Intercalation has been achieved by all three methods used, the gallery height ranging between 16.5 and 17.5 Å, depending on the particular drying conditions, these values suggesting the organic molecules form bilayers in the interlayer space.
Clay has always played a major role in human life. Clay raw materials are used and their value recognized in many economic branches, agriculture, civil engineering and environmental studies. This is largely because of their wide-ranging properties, high resistance to atmospheric conditions, geochemical purity, easy access to their deposits near the earth's surface and low price.Clay minerals, the essential constituents of argillaceous rocks, can be classified in seven groups according, to their crystal structure and crystal chemistry. Clay raw materials are divided in the same way into seven groups. An eighth group covers clay ochres and pigments. Further classification is based on the purpose-made technological application. Some examples show relations between the crystal structure or crystal chemistry of the dominant phyllosilicate and the technological properties. The chapter “Utilization of clay raw materials in industry and other human activities” is the most extensive. It gives information on the application of clay raw materials or individual clay minerals: in the production of foods, feedstuffs, beverages, paper, rubber, plastics, artificial leather, protective coatings for interior and exterior use, pharmaceutics, cosmetics, paints, pencils, pastels, porcelain, electro-porcelain and other fine ceramics, coarse ceramics and sialon ceramics; in the foundries, various branches of the chemical, petroleum and cement industries, agriculture and forestry; in the preparation of agrochemicals and special fertilizers, lubricating oils and gels, lightweight ceramics and effective sorbents; in the manufacture of mineral wool, in briquetting and pelletizing processes; as ingredients in grinding and polishing pastes, in the insulations of dumps of various kinds of waste (including toxic and radioactive waste), in thermally, electrically, acoustically and chemically resistant insulations, and in filters for the treatment of industrial, agricultural and similar outflows.The earth sciences use the clay minerals in the earth crust: (1) as indicators of the environment during weathering, allothi- and authigenesis in the sediments and in the study of the source areas of the detrital supply; (2) as pH indicators and indicators of processes in micro- and mega-environments and of changes in the course of diagenesis and metamorphosis. Mineralogical, petrological, geological and geochemical investigations directed to clay minerals serve as one of the correlation methods, in the recognition of processes in the petroleum-bearing sediments, coal-bearing formations, origin of riverine, lacustrine, marine and oceanic sediments and in the climatic, geodynamic, paleogeographical, stratigraphic and weathering rate interpretations.
Because of their high specific surface area, optimum rheological characteristics and/or excellent sorptive capacity, certain clay minerals such as kaolinite, talc, montmorillonite, saponite, hectorite, palygorskite and sepiolite are extensively used in the formulation of various pharmaceutical and cosmetic products. Whether as active ingredients or as ideal excipients, these minerals must comply with a number of textural and compositional requirements (concerning grain size, degree of mineral purity, water content, major and trace element contents or microbial contamination) and have specific technical properties. Their safety and stability characteristics are vitally important. This paper gives a review of the different pharmacopoeias, rules and regulations affecting the use of these natural products, whose denominations in the commercial sphere vary significantly. Particular attention is also paid to the different safety aspects associated with their processing, handling and administration.
This work examines the beneficial effects for human health of clay minerals, describing their use in pharmaceutical formulations, spas and aesthetic medicine. Their therapeutic action as active principles in pharmaceutical formulations orally administered (gastrointestinal protectors, laxatives, antidiarrhoeaics) or for topical applications (dermatological protectors and cosmetics) is described. Their use as excipients and their influence in the bioavailability of the organic active principle is also described, both in the liberation process and in its possible degradation effect. Among their uses in spas, clay minerals therapeutic activity, in geotherapy, pelotherapy and paramuds is commented upon. Moreover, the applications of the clay minerals in aesthetic medicine (to clean and moisturise the skin and to combat compact lipodystrophies, acne and cellulite) are also described.
The clay is a natural mineral resource that can be used for different applications: Recently some studies indicate that it can also be used for retention of gases at room temperature conditions. Several researchers study the retention of gases and have analysed physicochemical characteristics of the clays and their influence on capacities for adsorption gases. It has been demonstrated that the clays can be used as solid adsorbents in natural conditions and after modifications. In that way the natural smectite clays are better than natural kaolinites. Nevertheless, after appropriate physicochemical modifications, it is possible to obtain good adsorbents by using both types of clays as raw materials. Different activities related to our modern life, which have originated environment changes, have increased the emission pollutant gases and then have influenced health. Retention of gases by clays and their modified products which can help us to clean polluted atmosphere are shown in this review.
This work summarizes the beneficial and harmful effects of layered double hydroxides upon human health. Their possible uses in pharmaceutical formulations are present in many subjects: from classical applications as orally and topical drugs to new trends as cancer therapy. The application of layered double hydroxides as excipients and their influence on the bioavailability of the organic active principle is also reviewed. Clay-modified electrodes have received attention in the development of electrochemical sensors and biosensors. This article also reviews this aspect for medical purposes. Finally, a summary of the fields in which layered double hydroxides could be applied to prevent public health is also provided.
Clay minerals are included in several health care formulations. In particular, they are presented in many semisolid preparations with different functions, including stabilization of suspensions and emulsions, viscosizing and other special rheological tasks, protection against environmental agents, adhesion to the skin, adsorption of greases, control of heat release, etc. These functions are possible because of the special disposition of clay mineral particles when dispersed in polar solvents, due to their high surface areas and colloidal dimensions. When necessary, clays are processed or even modified to exalt or change some properties and new clay-like materials with special features are also synthesized. Finally, clays are frequently used concomitantly with other rheological modifiers to obtain synergic effects, influencing the stability and/or other technical properties of the health care products. This paper reviews the properties of clay mineral dispersions and the different functions derived from those properties, providing examples of applications in products intended to fulfil health care aims.
Hereby, it is considered the literature concerning the mobility of chemical elements from healing clays to the human body, including in vitro and in vivo studies with specific aim. Two main types of clay administration for healing uses are topical applications (usually in spa centres) and ingestion (either in a voluntary or unintentional way). The mechanism of element mobility is very different for the two applications. The topical use mainly involve soluble and exchangeable chemical elements, whereas the ingestion of clays is more effective due to great aggressive conditions into the stomach.Some poorly known implications of clay uses are mentioned, such as the effects of organic compounds in the transdermal migration of elements and the effective simulation of the digestion, that is in balance between chemical leaching and adsorptive effect of clays.
This review is focused on the pharmaceutical and biological applications of clays, clay minerals and layered double hydroxides (LDHs). Novel nanohybrids of clay mineral-/ or LDH-biomaterials, including vitamins, drugs, and DNA strands are discussed for possible future developments in cosmetics, pharmaceutics, medicine as well as information storage.
It is demonstrated that a variety of modified silicate mineral sorbents can be utilized for the removal of organic pollutants from a water suspension or by a filter. Column filters filled with a mixture of quartz sand and organic micelle–montmorillonite (100:1 w/w) or zeolite were constructed. The micelle–clay filter removed 91% of ethylene dibromide (EDB) from an initial solution of 0.2 μg/L and 99.9% of the anionic pollutants sulfosulfuron, imazaquin, sulfentrazone and the neutral bromacil and chlorotoluron from an initial solution of 10 ppm. In contrast a filter filled with activated carbon at the same weight of the organic cation and sand, or without sand removed between 47.6% and 79% of these pollutants. Comparative capacity measurements yielded removal of sulfentrazone (75 ppm initial) at weights corresponding to 18.7% and 5.5% of the weights of the organic cation or activated carbon in the filter, respectively. For the antibiotic trimethoprim the micelle–clay system was not efficient; the clay mineral montmorillonite and the zeolite clinoptilolite yielded respectively 80% and 99.9% removal from its dispersion. A clinoptilolite/sand filter gave 91% removal. We also present varying degrees of efficiencies of removal of isoproturon, benzoic acid, and 1,2 dichlorobenzene by an organo-clay and by silica (controlled pore glass (CPG))-polycation immobilized micelles (SPIM) or without immobilized micelles.
Medical geology is an emergent field of science that for some authors deals with the relationships between the geological environment and health problems in humans, animals and plants. Chemical elements, minerals, rocks, soils, water and air are the essential components of the geologic environment. Both quality and quantity of these components condition very much the living quality and the life duration, due to the beneficial and hazardous effects they have upon organisms, man, other animals, and plants. Medical geology is a multidisciplinary scientific field shared by specialists of distinct areas and scientific domains, such as earth sciences, environmental sciences, medicine, public health, biology, biochemistry, chemistry, pharmacy, nutrition, and others. Certain diseases are attributed to several minerals sensu latu (concept that includes the minerals sensu restrictu considered as natural, inorganic and crystalline solids, the so-called oligoelements or trace minerals, the biominerals and mineral resources such as natural mineral water), naturally or humanly derived. Within minerals, clay minerals, the essential constituents of clays, are omnipresent at the earth surface where organisms live, and due to their specific properties they can interact, positively as a rule, with them. Some clay minerals are being used, either as active principles (gastrointestinal protectors, laxatives, antidiarrhoeaics), or as excipients (inert bases, emulsifiers, lubricants) in certain medicines. Also they participate in formulations used for topical applications in both dermopharmacy and dermocosmetics.
Influences of pH and ionic strength on the aggregation of montmorillonite particles in the presence or absence of glyphosate (PMG) were studied. Adsorption isotherms and X-ray diffraction indicated that ligand exchange is the main mechanism of PMG adsorption. The surface coverage increased with the ionic strength and was more noticeable at high PMG concentration indicating inner-sphere surface complexation. At low PMG concentration the inner-sphere surface complexes are located of the external clay mineral surface while at high PMG concentration the surface complexes are also formed in the interlayer space.
The need for safe, therapeutically effective and patient-compliant drug delivery systems continuously leads researchers to design novel tools and strategies. Clay minerals are widely used materials in drug products both as excipients and active agents. When administered simultaneously, drug–clay interactions have been observed and studied, but until recently were not considered as a possible mechanism to modify drug release. In recent years, and based on their high retention capacities as well as swelling and colloidal properties, clays have been proposed as very useful materials for modulating drug delivery. This paper first reviews the studies on drug–clay interactions, and then those focused on the applications of natural clays and their semi-synthetic or synthetic derivatives to carry out specific functions in new drug delivery systems. In particular, clays are used to delay and/or target drug release or even improve drug dissolution. Finally, new strategies are reported for increasing drug stability and simultaneously modifying drug delivery patterns through the use of clay minerals.
Comparative study of the cooling rates of bentonite, sepiolite and common clays for their use in pelotherapy Compositional, technical and safety specifications of clays to be used as pharmaceutical and cosmetic products
- J L Legido
- C Medina
- M L Mourelle
- M I Carretero
- M Pozo
Legido, J.L., Medina, C., Mourelle, M.L., Carretero, M.I., Pozo, M., 2007. Comparative study of the cooling rates of bentonite, sepiolite and common clays for their use in pelotherapy. Applied Clay Science 36, 148–160 (this issue). doi:10.1016/j.clay.2006.06.014. López-Galindo, A., Viseras, C., Cerezo, P., 2007. Compositional, technical and safety specifications of clays to be used as pharmaceutical and cosmetic products. Applied Clay Science 36, 51–63 (this issue). doi:10.1016/j.clay.2006.06.016.
Clays in industry A Clay Odyssey
- H H Murray
Murray, H.H., 2003. Clays in industry. In: Dominguez, E.A., Mas, G.R., Cravero, F. (Eds.), A Clay Odyssey. Proceedings of the 12th International Clay Conference 2001. Elsevier, Amsterdam, pp. 3–14.
Comparison of saponite and montmorillonite behavior during static and stirring maturation with sea water for pelotherapy Clay minerals and layered double hydroxides for novel biological applications
- M I Carretero
- M Pozo
- C Sánchez
- F J Garcia
- J A Medina
- J M Bernabé
Carretero, M.I., Pozo, M., Sánchez, C., Garcia, F.J., Medina, J.A., Bernabé, J.M., 2007. Comparison of saponite and montmorillonite behavior during static and stirring maturation with sea water for pelotherapy. Applied Clay Science 36, 161–173 (this issue). doi:10.1016/j.clay.2006.05.010. Choy, J.-H., Choi, S.-J., Oh, J.-M., Park, T., 2007. Clay minerals and layered double hydroxides for novel biological applications. Applied Clay Science 36, 122–132 (this issue). doi:10.1016/j. clay.2006.07.007.
Clays. Ullmann's Encyclopedia of Industrial Chemistry
- H H Murray
Murray, H.H., 1986. Clays. Ullmann's Encyclopedia of Industrial Chemistry, vol. A7. VCH, Weinheim, pp. 109–136.
Minerals and Human Health. Benefits and Risks. (Os Minerais e a Saúde Humana
- C S F Gomes
- Pereira Silva
Gomes, C.S.F., Pereira Silva, J.B., 2006. Minerals and Human Health. Benefits and Risks. (Os Minerais e a Saúde Humana. Benefícios e Riscos) (in English and Portuguese). Centro de Investigação " Minerais Industriais e Argilas ", Departamento de Geociências da Universidade de Aveiro, Campus Universitário de Santiago, Portugal. 142 pp.