ArticleLiterature Review

The Use of Polyhydroxy Acids (PHAs) in photoaged skin

Authors:
  • Vitiligo & Pigmentation Institute of Southern California
  • NeoStrata Company Inc
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Abstract

The beneficial effects of alpha-hydroxyacids (AHAs) on skin were discovered by Drs. Van Scott and Yu in the early 1970s, including exfoliation, skin smoothing, and antiaging effects. A new generation of AHAs, called polyhydroxy acids (PHAs), was discovered that provide similar effects as AHAs but do not cause the sensory irritation responses that can limit the use of classical AHAs. PHAs have been found to be compatible with clinically sensitive skin, including rosacea and atopic dermatitis, and can be used after cosmetic procedures. PHAs provide additional humectant and moisturization properties compared with AHAs and can enhance stratum corneum barrier function, therefore increasing the skin's resistance to chemical challenge. Most PHAs also possess antioxidant properties. PHAs such as gluconolactone or lactobionic acid may be used in combination with other products, ingredients, or procedures such as laser and microdermabrasion to provide additional benefits to therapy or to enhance the therapeutic effect. Several studies were conducted in support of this, and methods and results are discussed. In summary, PHA-containing products were used in combination with retinoic acid in treating adult facial acne and were found to be well tolerated. PHAs plus retinyl acetate (pro-vitamin A) in a cream base exhibited significant antiaging skin benefits such as skin smoothing and plumping. PHAs plus hydroquinone showed excellent improvement in antiaging and skin lightening parameters. Finally, PHA-containing products were shown to be compatible with African American, Caucasian, and Hispanic/Asian skin and provided significant improvements in photoaging in these populations.

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... 27 PHAs are formulated as multiple strand molecules allowing for slower and gentler absorption rate, reducing aforementioned side effects, making them compatible for use on clinically sensitive skin. 28 One PHA, lactobionic acid, has been suggested to be an inhibitor of the breakdown of matrix metalloproteinase enzymes (MMPs), possibly due to metal chelation. Breakdown of these MMPs due to sun exposure contribute to the appearance of photoaging. ...
... Additionally, PHAs have strong moisturizing and humectant properties. 28 The combination of PHAs and tretinoin has been shown to decrease the total number of acne lesions and both subjective and objective measures of irritation. 28 Triclosan/triclocarban. ...
... 28 The combination of PHAs and tretinoin has been shown to decrease the total number of acne lesions and both subjective and objective measures of irritation. 28 Triclosan/triclocarban. Triclosan/triclocarban are bacteriostatic agents that can be found in a variety of household items and are often the key ingredient in OTC acne cleansers and washes. Triclosan is a bisphenol disinfectant, with action against gram-positive and most gram-negative organisms and is used in surgical scrubs/soaps and deodorants. ...
Article
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Acne is a common dermatological disorder that most frequently affects adolescents; however, individuals may be affected at all ages. Many people who suffer from acne seek treatment from both prescription and over-the-counter acne medications. Due to convenience, lower cost, and difficulty getting an appointment with a dermatologist, the use of over-the-counter acne treatments is on the rise. As the plethora of over-the-counter acne treatment options can be overwhelming, it is important that dermatologists are well-versed on this subject to provide appropriate information about treatment regimens and potential drug interactions and that their patients see them as well-informed. This article reviews the efficacy of various over-the-counter acne treatments based on the current literature. A thorough literature review revealed there are many types of over-the-counter acne treatments and each are designed to target at least one of the pathogenic pathways that are reported to be involved in the development of acne lesions. Many of the key over-the-counter ingredients are incorporated in different formulations to broaden the spectrum and consumer appeal of available products. Unfortunately, many over-the-counter products are not well-supported by clinical studies, with a conspicuous absence of double-blind or investigator-blind, randomized, vehicle-controlled studies. Most studies that do exist on over-the-counter acne products are often funded by the manufacturer. Use of over-the-counter acne treatments is a mainstay in our society and it is important that dermatologists are knowledgeable about the different options, including potential benefits and limitations. Overall, over-the-counter acne therapies can be classified into the following five major groups: cleansers, leave-on products, mechanical treatments, essential oils, and vitamins.
... They make cells proliferate and become metabolically more active as well as influence the skin lipids. The last factor keeps the skin in good condition [4]. Acid peels applied to the skin activate specific mechanisms, both chemical -amide bond hydrolysis and biochemical -inflammatory reaction. ...
... They are involved in the connective tissue remodelling process during which hyalur -onic acid and new collagen fibres production grows. It stimulates the natural regeneration processes in the skin, leading to the improvement of its physiological properties [1][2][3][4]. ...
Article
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Azelaic acid and mandelic acid are superficial peels commonly applied in people of various age groups. As they are mild and do not cause any side effects, they are also often used in elderly people. To compare the influence of azelaic and mandelic acid peels on facial sebum secretion in mature women aged 49-71 years. The level of secreted sebum was measured in 28 women. Eleven women were treated with azelaic acid peel and 17 with mandelic acid peel. Each of the peels was applied five times with 2-week intervals. The measurements were made on the cheeks and chin with the use of Sebumeter SM 15 (Courage & Khazaka, Germany). The last measurement, i.e. the sixth one, was made 2 weeks after the treatment. We observed a significant increase in sebum secretion in the U-zone after the application of 20% azelaic peel and 40% mandelic peel. Neither peel significantly affected sebum secretion in the T-zone. Peels with 20% azelaic acid and 40% mandelic acid might be considered treatments which contribute to an increase in sebum secretion in ageing women.
... In contrast, only Asian subjects showed increases in tanning on the exterior forearms. The use of PHAs on photoaged skin in several skin phototypes has also been recently investigated [46]; the results show that, in addition to several beneficial effects on skin physiology, PHAs elicit a significant skin lightening, although the mechanism by which that occurs has not yet been elucidated. Glycolic acid has recently been assessed with respect to its efficacy when used in combination with skin peels elicited by nonablative lasers, intense pulsed light, and trichloroacetic acid. ...
Article
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This paper describes recent data on the effects of various skin formulations containing hydroxyacids (HAs) and related products on sun-exposed skin. The most frequently used classes of these products, such as α - and β -hydroxyacids, polyhydroxy acids, and bionic acids, are reviewed, and their application in cosmetic formulations is described. Special emphasis is devoted to the safety evaluation of these formulations, particularly on the effects of their prolonged use on sun-exposed skin. We also discuss the important contribution of cosmetic vehicles in these types of studies. Data on the effects of HAs on melanogenesis and tanning are also included. Up-to-date methods and techniques used in those explorations, as well as selected future developments in the cosmetic area, are presented.
... Hydroxy and polyhydroxy acids have a long history as cosmetic products, thanks to their activity on the skin that favors hydration and renovation, and protects from oxidative damage, without toxic effects. 1 The addition of a sugar through an ether linkage such as galactose in LA confers on the molecule the ability to inhibit metalloproteases (MMPs) such as MMP-2 and MMP-9 2 and to efficiently chelate ferric ions. 3 These properties, together with its osmotic activity on cells, 4 make LA an ideal molecule for transplant organ preservation. ...
Article
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Purpose: The aim of this study was to investigate the properties of lactobionic acid (LA) as a possible supplement in artificial tears in in vitro and in vivo experimental model systems. LA is a bionic derivative of a polyhydroxy acid, which consists of one galactose attached by an ether link to a gluconic acid. It is a molecule endowed with several properties that make it an ideal supplement in artificial tears: it is highly hygroscopic and a powerful antioxidant, it is an iron chelator and inhibits matrix metalloprotease activity; it favors wound healing (WH); and it inhibits bacterial growth. Methods: Promotion of WH by LA, alone or in combination with hyaluronic acid (HA), was investigated in vitro on monolayers of rabbit corneal cells (Statens Seruminstitut) and in vivo after epithelium debridement of rabbit corneas. TGF-β expression and MMP-9 activity in wounded corneas were detected in tears and cornea extracts by western blot or by Enzyme Linked ImmunoSorbent Assay (ELISA). Bacterial growth inhibition by LA was checked on Staphylococcus aureus isolates in liquid culture. Results: LA, with or without HA, favors WH in vitro and in vivo. The WH assay on the rabbit cornea showed that 4% LA in association with 0.15% HA also resulted in a blunted increase of MMP-9 and TGF-β in tears and corneal tissue. Finally, the presence of 4% LA resulted in slower growth of cultured bacterial isolates. Conclusions: Our findings support the hypothesis that LA could be a useful supplement to artificial tears to treat ocular surface dysfunction such as dry eye.
... Ferric ions may generate free hydroxyl radicals: iron chelation prevents this chemical reaction [47] . Therefore, these 2 abilities, antioxidant and hygroscopic, make LA an ideal molecule for anti-ageing cosmetic treatment [48] and for transplant organ preservation [49] . Moreover, since iron is a necessary metabolite for bacterial growth [50] , it could be expected that LA, similarly to Lf, has antibacterial effects [51] . ...
Article
Full-text available
Dry eye is the most prominent pathology among those involving the ocular surface: a decrease of the aqueous (less frequent) or the lipid (more frequent) component of the tear film is the cause of the diminished stability of tears that is observed in this pathology. Dry eye shows a clear distribution linked to both sex (being more frequent among women) and age (increasing with aging). Therefore, specific treatments taking into account the etiology of the disease would be desired. The role of lactoferrin and its functional mimetic lactobionic acid are reported here as a possible remedy for age-related dry eye.
... Additionally, promoting the normal turnover of skin cells may be another useful approach to prevent skin aging. [47][48][49] 10-HDA may exert protection against damaging oxygenfree radicals through mechanisms similar to those of its analogous glycolic acid. These mechanisms include stimulating new cells in skin to generate elastic fibers, protecting skin from oxidative damage, and increasing deposition of hyaluronic acid filler in the dermis. ...
Article
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Abstract Honeybee (Apis mellifera) royal jelly (RJ) has a long history in human medicine because of its health-protecting properties. To develop a fundamental and comprehensive understanding of lipids in RJ, this article reviews the available literature on lipid compounds identified from RJ extracts and in vitro pharmacological effects of 10-hydroxy-2-decenoic acid in RJ and other closely related compounds, some of which are also identified as lipid compounds in RJ. Overall, the lipids in RJ are composed of mostly (aliphatic) fatty acids, almost all of which are present as free fatty acids and scarcely any as esters. Most fatty acids in RJ are medium-chain fatty acids, whether hydroxylated in terminal and/or internal positions, terminated with mono- or dicarboxylic acid groups, and saturated or monounsaturated at the 2-position. Besides these fatty acids, lipids in RJ contain sterols in minor amounts. Lipids in RJ are useful as preventive and supportive medicines with functionalities that include potential inhibitors of cancer growth, immune system modulators, alternative therapies for menopause, skin-aging protectors, neurogenesis inducers, and more. Taken together, the evidence suggests that health-protecting properties of RJ can be, in part, ascribed to actions of lipids in RJ.
... Lactobionic acid is an aldonic acid produced when lactose is oxidized [1,2]. The compound has several important applications, as in anti-ageing skin care [3], preservation of human organs for transplants [4], vectorization of antitumor drugs [5], and improvement of solubility of macrolide antibiotics [6]. As a potent sweetener, sorbitol (C 6 H 14 O 6 ) is used in the food industry, especially in the formulation of diabetes products [7], toothpaste [7,8], and vitamin C tablets [7]. ...
Article
Full-text available
Equimolar amounts of lactobionic acid and sorbitol may be obtained in a reaction catalyzed by the enzymes glucose-fructose oxidoreductase and glucono-δ-lactonase, which are found in the periplasm of Zymomonas mobilis. These reactions are generally conducted using immobilized bacterial cells, and the cell treatment and immobilization steps are costly and time-consuming. This study evaluated alternatives to simplify the preparation of calcium alginate-immobilized biocatalyst and its application in different operation modes and types of reactors. It was possible to eliminate cell permeabilization with cetyltrimethylammonium bromide, and the reticulation of Z. mobilis cells with glutaraldehyde sufficed to inhibit the fermentative metabolism of carbohydrates by the bacterium, with accumulation of bioconversion products. When the process was carried out in a mechanically stirred reactor in batch mode, 530 mmol L(- 1) of products were obtained in 24 h. The process was also tested in fed-batch mode so as to use of a larger amount of lactose, since it could not be used in the batch because of its low solubility in water. Under this condition, final products concentration reached 745 mmol L(- 1) within 42 h. Similar results were obtained for reactions conducted in a pneumatically stirred reactor in batch and fed-batch modes, proving the potential use of this process in several industrial settings.
... anti-free radical properties, LBA and sodium lactobionate have important applications in medicine and in the cosmetic industry [4,5]. ...
Article
The separation of lactobionic acid (LBA), a product of a biotechnological process catalyzed by the enzymes glucose-fructose oxidoreductase and glucono-δ-lactonase of the bacteria Zymomonas mobilis, was studied using ion selective membranes in electrodialysis (ED). The recovery of LBA, present in a solution with a concentration of 20 g L–1, was 38.7% in 250 min of testing for an electrical potential difference of 15 V. When compared with a solution containing all the components present in the bioconversion (lactose, fructose, and sorbitol), the recovery was inhibited by the presence of non-ionic substances and the LBA recovery efficiency decreased to 16.2%. The same behavior was observed when a Z. mobilis bioconversion medium was used, with a recovery of 14%. Despite the low recovery efficiency the high specificity in relation to the other bioconversion components makes this process suited for LBA production.
... Comparative studies of hygroscopic agents (glycerol (33 g.mol −1 ), sorbitol (14 g.mol −1 ), glycolic acid (4 g.mol −1 ), citric acid (8 g.mol −1 ), and lactic acid (moisture loss rather than gain) show a greater capacity of water retention of LBA (54 gmol −1 ) (Grimes, Green, Wildnauer, & Edison, 2004;Pharmanostra, 2017;Yu, & Van Scott, 2004). In 2012, the LBA was studied for application in meat products with the purpose of retaining moisture, after a cycle of freezing and thawing, with positive result compared with the control samples (Gutiérrez et al., 2012b). ...
Article
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The chemical configuration of the lactobionic acid (LBA) evidences its potential properties, among which the antioxidant, antimicrobial, and chelating activities stand out in the literature. However, few studies aim at testing and confirming them. The purpose of this study was to determine some selected LBA properties, whose characteristics are of interest for its use as an ingredient in foodstuffs. The discussion followed the results of Fourier‐Transform Infrared Spectroscopy (FTIR), X‐ray diffractometry (XRD), 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical, 2,2′‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulphonic acid) (ABTS) radical, thermogravimetric/derivative thermogravimetry (TGA/DTG), minimal inhibitory concentration (MIC) by the diffusion disk test, scanning electron microscopy (SEM), and iron/calcium chelating methodologies. The XRD analysis revealed the presence of an amorphous halo and the absence of defined peaks, a fact possibly related to its high hygroscopicity. The FTIR showed characteristic bands of the LBA structure. Results from TGA/DG verified the LBA thermal degradation, which evidenced that LBA could participate in most food industry unit processes within the first mass loss event. Antioxidant capacity reached a maximum inhibition of 56% for LBA and the chelating capacity of the iron ion achieved 54% of chelated ions, while the calcium ions reached 15%. The results revealed high potential of LBA application for microbial inhibition, moisture retention, and texture maintenance throughout storage of food products. Practical Applications Despite the potential of application of the LBA, few quantitative results demonstrate its ability of action in food. Even without permission in most countries around the world, more research with LBA will encourage the investigation of its toxicology, expanding the areas of application. Its thermal degradation profile and elevated solubility demonstrated the potential of LBA as food ingredient, performing moreover as antioxidant, chelating agent, antimicrobial, and texturizer. The results open the possibilities for many applications in the field of food chemistry and food industry.
... 9 Traditional routes include the use of sunscreens, but inhibition of melanocyte activity, reduction in melanosome transfer and dendricity together with the accelerated removal of melanin by inducing epidermal proliferation are typical. 9 Typical actives include retinoids, 10-12 niacinamide, [13][14][15][16] kojic acid, 17 arbutin and derivatives, 18,19 bisabolol, 20 soybean trypsin inhibitors, 21 azelaic acid, 22 licorice derivatives such as Glabrene and isoliquiritigenin, 23 vitamin C derivatives and other antioxidants, 24 N-acetyl glucosamine, 25,26 N-undecy-10-enoyl-L-phenylalanine, 27 hydroxyacids 28,29 and octadecenedioic acid. [30][31][32] To develop new potential ingredients for skin-lightening products, we have focused on the inflammatory pathways involved in skin pigmentation. ...
Article
Irregular skin pigmentation may be a substantial contributor to the signs of aging and to a person's lack of psychological well-being. Although a large number of skin-lightening agents are available, the opportunity exists to identify more efficacious agents, agents that target alternative biological mechanisms. Aims: To provide clinical evidence of the skin-lightening effect of the tetrapeptide, Pro-Lys-Glu-Lys (PKEK), on subjects with skin types V-VI living in South Africa. Pro-Lys-Glu-Lys was evaluated in a double-blind and vehicle-controlled clinical study using expert grading of digital images by comparing its effects in subjects with skin types V-VI suffering from facial melasma and postinflammatory hyperpigmentation. This study demonstrated the efficacy of PKEK on subjects with skin types V-VI. On comparing the two treatments, the skin-lightening peptide-containing formulation was significantly superior to the vehicle at 12 weeks on overall appearance (P < 0.05) and evenness of skin tone (P < 0.01). The tetrapeptide, PKEK, has proven skin-lightening benefits on skin discoloration from melasma and postinflammatory hyperpigmentation. These studies have been conducted on subjects with skin types V-VI living in South Africa, but we believe this technology to be suitable for all racial groups.
... Both barrier homeostasis and stratum corneum functionality are clearly improved when LBA is applied topically (Hachem et al., 2010). LBA in fact constitutes an inhibitor of the breakdown of matrix metalloproteinase enzymes due to metal chelation, thus reducing the appearance of photoageing and wrinkles (Grimes et al., 2004). In addition to LBA's antioxidant role, it also exhibits strong moisturizing, exfoliative and humectant properties, which expand its commercial relevance within the cosmetics field (Yu and Van Scott, 2004). ...
... Herein, a PHBHV is employed and is preferred to PHB due to its better flexibility [27]. PHAs have been considered for several different application fields, like the medical sector [30]- [32], cosmetics [33], packaging [23], [34]- [37] or toys [38]. Depending on the targeted applications and the expected material structure, PHA was processed by different techniques, including by phase inversion (Table 1). ...
Article
Within the purpose of developing more sustainable membrane systems, it is herein proposed to implement a biobased and biodegradable material, the poly(hydroxybutyrate-co-hydroxyvalerate) (PHBHV), to replace conventional polymers in a commonly used membrane fabrication process. The PHBHV based membranes were made by non-solvent induced phase separation (NIPS) using N-methyl-2-pyrrolidone (NMP) as solvent. The process parameters and dope solution composition were developed in order to give structures suitable for performances characterization. In that sense, the microstructures were characterized in case of non-supported and supported membranes. The addition of hydrophilic additives, ethylene glycol (EG) and polyethylene glycol 300 g mol⁻¹ (PEG300), was linked to the morphology changes. Porous asymmetric membranes were obtained in case of the non-supported membranes or supported membranes with a low amount of additive (1 wt%). Otherwise, symmetric porous membranes, made of interconnected crystal lamellas, were observed. The particularly high crystallinity of this biomaterial involved some different microstructures compared to classic polymers. Both types of structures demonstrated decent rejections of a clay dispersion. Due to the increased pore size, the permeabilities were greatly improved with the additives and values up to 480 L m⁻² h⁻¹.bar⁻¹ were achieved.
... AHA and PHA products are categorized as antiaging products, which help restore damaged or aging skin. 75 Vitamin A (retinol) is a common product in skin preparations. To be active, retinol must be converted to retinoic acid by enzyme activity in the stratum corneum. ...
... However, excessive production of melanin is associated with deteriorative forms of hyperpigmentation, such as age spots, freckles and melasma, and postinflammatory hyperpigmentation [180]. Melanogenesis-related skin problems have been addressed using tyrosinase inhibitors such as hydroquinone, arbutin, ascorbic acid, and azelaic acid as skin lightening agents and materials such as hydroxy acids, which exfoliative corneocytes, revealing lighter and smoother skin [181]. However, several adverse effects including chemical instability, skin irritation, and contact dermatitis [178] prompted demand for safer natural alternatives. ...
Chapter
The application of microbially derived biosurfactants can be of great benefit in the industrial production of personal care and detergent-based products. Both product categories have common features: dependence of their production on large amounts of synthetic surfactants, widespread daily life usage by the general population worldwide, and unwise disposal, posing significant health and environmental risks. There is a currently increasing demand for more ecocompatible products and safer ingredients, driven by industrial sustainability, environmental awareness, and new regulations. Microbially based biosurfactants offer great benefits in this respect. Additionally, biosurfactants possess a high surface activity and directly associated functional properties and antimicrobial activity of high relevance to the personal care and cleaning industries. This chapter briefly highlights the advantages and functional properties of biosurfactants critical to their application in these industries. It also provides an updated overview of the evolution of biosurfactants in the development of different personal care and detergent-based cleaning products.
... LBA45 and LP45 showed the lowest PS values, so the presence of LBA in the edible films made them less resistant. LBA molecules are very hygroscopic (54 g mol −1 ) in comparison with other agents such as glycerol (33 g mol −1 ) or sorbitol (14 g mol −1 ) [40] and have a greater capacity to retain water [4]. Due to these characteristics, the presence of LBA makes the films thicker but mechanically weaker. ...
Article
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Cheese whey, one of the most abundant by-products of the dairy industry, causes economic losses and pollution problems. In this study, deproteinised sweet whey was fermented by Pseudomonas taetrolens LMG 2336 to produce a prebiotic compound (lactobionic acid, LBA). Endo-toxins produced by these microorganisms were successfully removed using microfiltration techniques , allowing the fermented whey permeate to be used in the food industry. The fermented whey permeate was used to develop prebiotic edible films by adding two different concentrations of gelatine (0.45 and 0.9 g gelatine g −1 LBA; LBA45 and LBA90). Furthermore, Lactobacillus plantarum CECT 9567 was added as a probiotic microorganism (LP45 and LP90), creating films containing both a prebiotic and a probiotic. The mechanical properties, water solubility, light transmittance, colour, and microstructure of the films were fully characterised. Additionally, the LBA and probiotic concentration in LP45 and LP90 were monitored under storage conditions. The strength and water sol-ubility of the films were affected by the presence of LBA, and though all these films were homogeneous , they were slightly opaque. In LP45 and LP90, the presence of LBA as a prebiotic improved the viability of L. plantarum during cold storage, compared to the control. Therefore, these films could be used in the food industry to coat different foodstuffs to obtain functional products.
... Lactobionic acid is functionally similar to AHAs in terms of enhanced cell turnover activity but it is also a strong humectant, a chelator, an inhibitor of matrix metalloproteinases, and an antioxidant that inhibits lipid peroxidation. [42][43][44] ...
Article
This article focuses on nonprescription home-use topical treatment technologies for the aging face and is intended to serve as a guide for the core cosmeceutical technologies currently used and to help educate and assist the selection of topical antiaging products by the professional staff and their patients. Antiaging topical treatments for patient home use should be nonirritating, compatible with the patient skin type, effective, and complementary to surgical and minimally invasive office procedures, and aesthetically elegant. New topical antiaging technologies, formulated as monotherapy or as combinations with well-known cosmeceuticals, should present adequate clinical studies to support their selection for use.
... The study used the methodological approach which considered separated symptoms and side effects, and which is in accordance with the contemporary description of other authors (Erbagci and Akcali, 2000). The current study determined the state of objective parameters (comedones, papules, papulopustules and the greasy face look), which is in accordance with the reports of Grimes et al. (2004) and Kim et al. (1999). Namely: the aforementioned authors confirmed a reduction in objective parameters. ...
Article
Chemical peeling of the skin involves the topical application of a chemical agent in order to produce a controlled injury to a desired depth, thus allowing subsequent regeneration of the skin which can result in improved texture, more homogeneous pigmentation and less wrinkling. Acne vulgaris is one of the most common skin diseases. The aim of the actual study was to examine and compare the efficiency, skin tolerance and side effects of a 35% glycolic acid combined with antibiotic therapy in patients with inflammatory aspects of acne. The sample consisted of 120 subjects, divided into two experimental sub-samples of 60 subjects each. The first sub-sample consisted of patients with acne papulosa, while the second sub-sample consisted of patients with acne papulopustulosa. The patients from both sub-samples were additionally divided into two groups of 30 patients each. To the first group of 30 patients (within each sub-sample, respectively), glycolic acid in a concentration of 35% was applied after adjusted antibiotic therapy, while to the second group of 30 patients (within each sub-sample, respectively) glycolic acid in a concentration of 35% was applied without previous adjustment of antibiotic therapy. In each sub-sample, the differences in the manifested symptoms of the ailment and the side effects were analyzed. Glycolic acid had a significant effect in the treatment of acne papulosa and acne papulopustulosa, as a monotherapy, as well as combined therapy, that is, after adjusted antibiotic therapy. Side-effects were experienced by patients treated only by glycolic acid, that is, without previously adjusted antibiotic therapy. Glycolic acid chemical peels in concentration of 35% had overall efficiency and a superior therapeutic effect and are recommended by the authors after adjusted antibiotic therapy. The appearance and intensity of side effects in patients after adjusted monotherapy, adduced us to the choice of combined therapeutic treatment.
... Lactobionic acid has many applications in the cosmetics (Green et al. 2009;West 2004), pharmaceutical Microbial Production of Organic Acids 103 (Belzer et al. 1992), food and chemical industries (Gerling 1998). Several brands of cosmetics are currently employing LBA as a key component of novel antiaging products, claiming to reduce photoaging and wrinkles (Grimes et al. 2004), and as a keratinization agent and regenerative skincare product (Green et al. 2009). ...
Article
The separation of quaternary mixtures of lactobionic acid, lactose, sorbitol and fructose using a gel-type ion-exchange resin loaded with H+, K+ and Ca2+ ions has been investigated. This separation is relevant in order to improve the productivity of lactobionic acid obtained from the enzymatic reaction catalyzed by Glucose–fructose oxidoreductase and glucono-δ-lactonase enzymes. Measurement of the single-component equilibrium isotherms for all four species was carried out in a preparative column packed with the selected resin at temperatures of 293, 313 and 333K using the frontal analysis and column adsorption–desorption method. Mass transfer coefficients for all species at different temperatures have been estimated by solving the dynamic model of the chromatographic column. From pulse tests of single-component and mixture solutions, the K+ loaded resin was found to be suitable for this quaternary separation. The unfavourable adsorption isotherm for the lactobionic acid is described by the anti-Langmuir model. Other compounds have shown linear equilibrium in the concentration range up to 130gL−1. Binary and quaternary fixed-bed experiments were well described by the dynamic model using the parameters obtained from the single-component adsorption data.
Chapter
IntroductionSoaps and syndetsBenzoyl peroxideSalicylic acidAlfa-hydroxy acidsPoly hydroxy acidsSulfurTriclosan and triclocarbanRetinolsCleansing clothsEssentialoilsOral vitaminsMechanical treatmentsConclusions References
Article
In this work the periplasmic enzymatic complex glucose-fructose oxidoreductase (GFOR)/glucono-δ-lactonase (GL) of permeabilized free or immobilized cells of Zymomonas mobilis was evaluated for the bioconversion of mixtures of fructose and different aldoses into organic acids. For all tested pairs of substrates with permeabilized free-cells, the best enzymatic activities were obtained in reactions with pH around 6.4 and temperatures ranging from 39 to 45 °C. Decreasing enzyme/substrate affinities were observed when fructose was in the mixture with glucose, maltose, galactose, and lactose, in this order. In bioconversion runs with 0.7 mol l(-1) of fructose and with aldose, with permeabilized free-cells of Z. mobilis, maximal concentrations of the respective aldonic acids of 0.64, 0.57, 0.51, and 0.51 mol l(-1) were achieved, with conversion yields of 95, 88, 78, and 78 %, respectively. Due to the important applications of lactobionic acid, the formation of this substance by the enzymatic GFOR/GL complex in Ca-alginate-immobilized cells was assessed. The highest GFOR/GL activities were found at pH 7.0-8.0 and temperatures of 47-50 °C. However, when a 24 h bioconversion run was carried out, it was observed that a combination of pH 6.4 and temperature of 47 °C led to the best results. In this case, despite the fact that Ca-alginate acts as a barrier for the diffusion of substrates and products, maximal lactobionic acid concentration, conversion yields and specific productivity similar to those obtained with permeabilized free-cells were achieved.
Article
Introduction. Acne vulgaris is a common, chronic skin disease that shows a characteristic clinical picture. Skin lesions occur primarily in the seborrheic areas of the body, i.e., the face, back, and chest. Mandelic acid yields very good results when used to treat excessive actinic keratosis (keratosis actinica), hyperpigmentation (lentigo solaris and melasma), and meshlike wrinkles, which are primarily caused by sun-induced aging of the skin. This therapy is well suited for the care of skin with acne vulgaris. Objective. To evaluate the efficacy of dermo-cosmetics containing 5% or 10% mandelic acid for the skin care of patients with acne vulgaris. Material and methods. An open study was carried out on 60 patients with papulo-pustular acne, who applied dermocosmetics to their skin for 2 months. Patients were divided into two subgroups of 30 patients each. One group was tested with a 5% mandelic acid containing cosmetic while the other group was tested with a 10% mandelic acid containing cosmetic. After the treatment was completed, acne severity was evaluated according to the Hellgren-Vincent scale. Results. Physical examinations performed during the study revealed a gradual improvement in the condition of the skin in both groups, with a reduction in the number of pustules, inflammatory nodules, and comedones. The proportion of patients in each group showing a reduction in disease severity according to the Hellgren-Vincent scale was similar. Conclusions. The results of the present study show that products containing 5% or 10% mandelic acid are both safe and effective for the treatment of acne.
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Like the entire human organism, the skin is subject to an intrinsic unpreventable aging process. But exogenous factors also influence skin aging. Ultraviolet radiation in particular results in premature skin aging, also referred to as extrinsic skin aging or photo aging, causing in large part aging-associated changes in sun-exposed areas. Intrinsic and extrinsic aging share several molecular similarities despite morphological and pathophysiological differences. The formation of reactive oxygen species and the induction of metalloproteinases reflect central aspects of skin aging. Accumulation of fragmented collagen fibrils prevents neocollagenesis and accounts for further degradation of extracellular matrix by means of positive feedback regulation. The importance of extrinsic factors in skin aging and the detection of its mechanisms has given rise to development of various therapeutic and preventive strategies.
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Like the entire human organism, the skin is subject to an intrinsic unpreventable aging process. But exogenous factors also influence skin aging. Ultraviolet radiation in particular results in premature skin aging, also referred to as extrinsic skin aging or photo aging, causing in large part aging-associated changes in sun-exposed areas. Intrinsic and extrinsic aging share several molecular similarities despite morphological and pathophysiological differences. The formation of reactive oxygen species and the induction of metalloproteinases reflect central aspects of skin aging. Accumulation of fragmented collagen fibrils prevents neocollagenesis and accounts for further degradation of extracellular matrix by means of positive feedback regulation. The importance of extrinsic factors in skin aging and the detection of its mechanisms has given rise to development of various therapeutic and preventive strategies.
Article
The exposure of human skin to environmental and artificial ultraviolet irradiation has increased significantly. This is not only due to an increased solar UV irradiation as a consequence of the stratospheric ozone depletion, but also the result of an inappropriate social behaviour with the use of tanning parlors being very popular. Besides this, leisure activities and living style with travelling to equatorial regions also add to the individual annual UV load. Since the population in industrialised countries shows an increasing total life span, in parallel the cumulative life time dose of solar and artificial UV-irradiation is dramatically augmented. In addition to the common longterm detrimental effects like immunosuppression and skin cancer, the photooxidative damage due to energy absorption of UV photons in an oxygenized environment leads to alterations of cells, subcellular compartments and macromolecules. The clinical manifestations of UV/ROS induced disturbances result in photoaged skin with wrinkle formation, laxity, leathery appearance as well as fragility, impaired wound healing and higher vulnerability. Strategies to prevent or to minimize photoaging and intrinsic aging of the skin necessarily include protection against UV irradiation and antioxidant homoeostasis. New developments of therapeutic interventions including DNA repair enzymes will be discussed.
Article
In the current study, superparamagnetic magnetite nanoparticles were surface-modified with lactobionic acid (LA) to improve their intracellular uptake and ability to target hepatocytes. Maltotrionic acid (MA)-modified nanoparticles were also synthesized as a control. Cell culture experiment showed that LA-modified nanoparticles were internalized into hepatocytes and atomic absorption spectrometer (AAS) measurement indicated that the uptake amount of LA-modified magnetite into hepatocytes was higher than that of unmodified and MA-modified nanoparticles. LA-modified nanoparticle solution was injected in rabbit and the magnetic resonance (MR) images obtained showed that LA-coated nanoparticles were selectively accumulated onto the hepatocytes. This result demonstrates that the LA-modified magnetite nanoparticles have a great potential to be used as contrast agent for liver diagnosis.
Article
The aging population and a desire to maintain a youthful appearance have propelled the recent surge in the U.S. cosmeceuticals market. The rapidly growing number of products claiming to diminish fine lines and wrinkles, decrease redness, smooth texture, and fade discoloration has lead to much confusion and misinformation among dermatologists and consumers alike. Cosmeceuticals can be a useful adjunct to prescription medications and office procedures. Therefore, it behooves us as dermatologists to understand the science behind these products to better educate ourselves and our patients. We present an update of the following categories of cosmeceuticals: antioxidants, growth factors, peptides, anti-inflammatories/botanicals, polysaccharides, and pigment-lightening agents.
Article
Die Belastung der Haut mit natürlicher und künstlicher UV-Strahlung hat in den letzten Jahren nicht nur durch die verstärkte solare Strahlung als Folge der Ozonabnahme in der Stratosphäre, sondern auch durch ein Freizeitverhalten mit dem Wunsch nach gebräunter Haut deutlich zugenommen. Dieser Wunsch wird nicht nur durch Reisen in die sonnigen Gebiete der Erde, sondern auch durch den häufigen Besuch von Solarien umgesetzt. Hinzu kommt die gestiegene Lebenserwartung in den Industrienationen, die mit einer gesteigerten kumulativen UV-Belastung korreliert. Konsequenz daraus ist zusätzlich zu Immunsuppression und Hautkarzinogenese auch die Photo- oder Lichtalterung der Haut durch den photooxidativen Schaden an Zellen, subzellulären Kompartimenten und Makromolekülen, der durch die Absorption von Photonen in einer sauerstoffreichen Umgebung entsteht. Klinisch manifestiert sich die Photoalterung der Haut in Faltenbildung, Gewebeschlaffheit, ledrigem Erscheinungsbild mit Fragilität, Verletzbarkeit und eingeschränkter Wundheilung. Strategien zur Vermeidung oder Minimierung dieser photooxidativen Langzeitschäden umfassen effektiven UV-Schutz und das Aufrechterhalten eines oxidativ-antioxidativen Gleichgewichtes in Zellen und Geweben. Neuere Therapieentwicklungen wie der Einsatz von DNA-Reparaturenzymen werden ebenfalls diskutiert.
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The Food, Drug, and Cosmetic Act defines drugs as products that cure, treat, mitigate or prevent disease, or affect the structure or function of the human body [1]. The dermatology and cosmetic industries recognize “cosmeceuticals” as cosmetics that have drug-like benefits. The term “cosmeceutical” was first used by Dr. Albert Kligman to describe a cosmetic product that exerts a therapeutic benefit in the appearance of the skin, but not necessarily a biologic effect on skin function, which would then classify it as a drug [2–4]. The Food and Drug Administration does not recognize or regulate cosmeceuticals. The symbiotic relationship between a drug and a cosmetic has become increasingly evident with the rapid growth of the cosmeceutical industry over the last decade. There are now both prescription cosmeceuticals and over-the-counter cosmeceuticals available to consumers. This arbitrary distinction varies in different countries. For example, drugs such as tretinoin, available only by prescription in the United States, are sold as over-the-counter cosmeceuticals in Central America. Antiperspirant is also regulated as a drug in the United States while being considered a cosmetic in Europe.
Article
In summary, multiple studies have documented the efficacy of topical agents (retinoids, antioxidants, and topical bleaching agents) used in combination with superficial and/or mediumdepth or deep peeling agents for photodamage. The treatment of photodamage requires a multifaceted approach incorporating sun protection, antioxidants, exfoliating agents, retinoids, and resurfacing procedures. Despite the evolution of new and advanced laser technologies, chemical peeling remains a viable, efficacious, and cost-effective treatment for photodamage.
Article
The interest in lactobionic acid (LA) in nano-pharmaceuticals is growing due to its selective affinity to liver cells. Currently there is no suitable analytical method for the determination of LA in nanoparticles or other matrices. There is a need for a quantitative assay to accurately determine LA in nano-particles as well as in other matrices. In this study, a HILIC-MS/MS method was developed and validated for the analysis of LA. The method was applied for the assessment of chitosan nanoparticles (CNP) functionalization. The developed method was valid for the determination of LA with a LOD and LOQ of 1 and 5 ng/mL, respectively. The method was applied for the determination of unreacted LA after nanoparticle functionalization and revealed that a loading-capacity of 24 % was achieved. In conclusion, the developed method is the first report for the quantitative determination of LA functionalization on nanoparticles. The method can be directly applied in the quality-control applications for the assessment of nanoparticle functionalization with LA and may be extended for quality control applications of other LA-containing products.
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This chapter covers hydroxyacids (HAs), including Alpha‐hydroxyacid (AHAs), Beta‐hydroxyacid (BHAs), Poly hydroxy acids (PHAs), aldobionic acids, and aromatic hydroxyacids. The AHAs are the most widely studied and commercialized ingredients within the HA family. The BHAs are organic carboxylic acids with one hydroxyl group attached to the beta position of the carboxyl group. The PHAs are organic carboxylic acids that possess two or more hydroxyl groups in the molecule. Most PHAs, bionic acids, and some AHAs and BHAs with one hydroxyl group and two or more vicinal carboxyl groups have been found to be antioxidants. AHAs and PHAs have been evaluated to determine whether daily application alters the sensitivity of normal human skin to UVB radiation. Matrix metalloproteinase enzymes provide a vital metabolic function by digesting the skins degraded and aged extracellular matrix components. Several substances have been used to date as peeling agents; these include phenol, trichloroacetic acid, salicylic acid, and AHAs.
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A plethora of over‐the‐counter (OTC) modalities exists for treating acne. These modalities include topical cleansers, creams, lotions, gels, and masks as well as mechanical treatments, essential oils, and oral vitamins. The Food and Drug Administration is the regulatory agency that presides over the marketing of non‐prescription acne products. Benzoyl peroxide is commonly found in OTC antiacne washes, creams, and lotions. Benzoyl peroxide acts as an anti‐inflammatory agent by reducing oxygen free radicals and also by lessening C. acnes density. The hydroxy acids are another common OTC antiacne ingredient found in washes and leave‐on products. Lipohydroxy acids, a derivative of salicylic acid, have a similar mechanism of action. Azelaic acid is an aliphatic, dicarboxylic acid used as a topical application in the treatment of acne vulgaris. Retinols are a group of vitamin A derivatives that are available topically OTC in various forms such as retinol, retinyl propionate, and retinyl palmitate.
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The key factor for promoting bioeconomy and circularity in the cities is to examine waste streams such as municipal wastewater, sludge, solid waste, food waste, bakery industry waste, and pulp and paper industry waste as raw materials rather than wastes to be disposed. In this regard, biorefinery concept is promising for converting biomass into valuable products. Biomethane, high market value volatile fatty acids, and polyhydroxyalkanoates are some of the main outstanding products for waste biorefineries. Algal biorefinery concept is also promising as serving as a multiple product factory that can also be integrated with municipal wastewater systems. Phosphorus recovery is also essential to control eutrophication in the receiving water bodies and reversing phosphorus back to the market. Therefore, future management of cities should include these specified approaches to support circularity and minimize possible environmental problems.
Article
Background Dry skin, caused by improper care or genetic conditions, can affect people of all ages. Skin hydration is determined its lipid content, which inhibits water loss from the epidermis, as well as other substances such as polyhydroxy acids and gluconolactone that can bind water. The aim of this study was to evaluate skin hydration after the application of 10% and 30% gluconolactone solution in a split face model. Materials and methods Sixteen healthy women were qualified for the study. Three split face treatments were performed, with 10% and 30% gluconolactone solution applied to two sides of the face. Skin moisture was measured before each treatment and a week after the last treatment at three measurement sites on either side of the face, that is, on the forehead, around the eye and on the cheek. Results Corneometric measurements showed a significant increase in facial skin hydration after gluconolactone treatment. No significant differences were observed between the application of 10% and 30% solution. Conclusion Gluconolactone is a moisturizing substance which works well in dry skin care.
Article
Physiological oxygen concentration (physioxia) ranges from 1 to 8% in human tissues while many researchers cultivate mammalian cells under an atmospheric concentration of 21% (hyperoxia). Oxygen is one of the significant gases which functions in human cells including energy production in mitochondria, metabolism in peroxidase, and transcription of various genes in company with HIF (Hypoxia-inducible factors) in the nucleus. Thus, mammalian cell culture should be deliberated on the oxygen concentration to mimic in vivo physiology. Here, we studied if the cultivation of human skin cells under physiological conditions could affect skin significant genes in barrier functions and dermal matrix formation. We further examined that some representative active ingredients in dermatology such as glycolic acid, gluconolactone, and salicylic acid work in different ways depending on the oxygen concentration. Taken together, we present the importance of oxygen concentration in skin cell culture for proper screening of novel ingredients as well as the mechanistic study of skin cell regulation.
Article
Within the current increasing environmental restrictions, biopolymers tend to replace common materials in many applications, from daily life items to process engineering facilities. Synthetic filtration membranes are also of concern. Herein, biopolymer based microfiltration (MF) membranes were produced with a polyhydroxyalkanoate (PHA), the poly(hydoxybutyrate-co-hydroxyvalerate) (PHBHV). The membranes were made by evaporation induced phase separation (EIPS) and the influence of the dope solution composition was studied by adding additives, polyvinylpyrrolidones (PVPs) and polyethylene glycols (PEGs). The nature, molecular weight and concentration of the additives were linked to the obtained microstructures. Both types of additives can increase membrane porosity by acting as pore former agent. However, interesting opposite effects were obtained in case of PEGs from 300 to 4000 g mol⁻¹ where the additives were observed to act as plasticizers. The membranes performances were evaluated with pure water permeability and E. Coli bacteria rejection and correlated to the microstructure analyses. The performances were greatly improved by selecting the proper additive. This study leads to promising results for the consideration of PHA as new potential biomaterial intended for membrane fabrication.
Article
The bioproduction of lactobionic acid and its salts can be performed by enzymatic complex glucose-fructose oxidoreductase (GFOR) and glucono-δ-lactonase (GL) of Zymomonas mobilis. Considering the applicability of these compounds in pharmaceutical area, the aim of this study was to assess the accelerated and long-term stability studies of sodium, potassium, calcium lactobionate, and lactobionic acid. Furthermore, stress tests were performed to evaluate the stability against pH, temperature and oxidation. The samples submitted to degradation tests were analyzed by high-performance liquid chromatography (HPLC) and high-resolution mass spectrometry analysis (HRMS-ESI-QTOF). Sodium, potassium, and calcium lactobionate were stable for six months of analyses considering the accelerated (40 °C and 75% RH) and long-term (30 °C and 75% RH) stability studies. The presence of lactobiono-δ-lactone and a significant increase in moisture were observed for both biosynthesized and commercially available lactobionic acid samples. Against the forced degradation tests, all the lactobionate salts and lactobionic acid showed to be stable upon alkaline and acid pH conditions, at 60 and 80 °C, and also against UV light exposition. Furthermore, the presence of lactobiono-δ-lactone form was observed in lactobionic acid samples. However, the degradation of both lactobionic acid and lactobionate salts was evident in the presence of hydrogen peroxide. This degradation kinetic profile suggests, that lactobionate salts follows a zero-order reaction model and lactobionic acid follows a second-order kinetic. The MS analysis of the main degradation product suggests a molecular formula C11H20O10 resulting from the oxidative decarboxylation. This report brings an amount of results as contribution to the scarce information regarding the chemical and physical-chemical stability of sodium, potassium, calcium lactobionate, and lactobionic acid. These data may be useful and serve as reference, in view of the multipurpose applications of the cited compounds.
Article
The past decade has witnessed the progression of the field of cosmeceuticals moving toward one of cosmoleculars™. The impact of advanced technologies as well as pharmaceutical methods and drug delivery systems has resulted in the field of cosmetic dermatology. This chapter will attempt to give the practitioner a base of current knowledge in the field of cosmetic dermatology. The skin care consumer has been faced with a literal flood of products into the marketplace designed to address various cosmetic concerns. As research and development of new bioactive ingredients and knowledge of existing ingredients continue to grow, and new technologies reflect increased stability and delivery of these ingredients to the skin, this trend will only continue to grow.
Article
Background Due to internal or external factors, the desquamation (turnover) rate of the stratum corneum slows down, resulting in skin problems. Therefore, adjusting the exfoliation rate through cosmetics is an important issue. Objective This report aimed to develop exfoliating agents with lesser adverse effects and higher efficiency through an ex vivo screening method and in vivo turnover rate analysis of human skin. Methods Various molecules were evaluated by the ex vivo porcine skin exfoliation method and screened for their potential as effective agents. To confirm the effect and mechanism of each agent found, the exfoliation efficiency was evaluated. Each agent was also applied to the actual human skin to determine its efficacy and side effects. Results Despite the pH 6, carnitine and serine, which have similar or better efficiency compared to PHA, were selected. Based on the results, it was confirmed that calcium. And it is nonirritating to the human skin and increases the turnover rate (~130%). Conclusion Amino acid‐based exfoliating agents, such as carnitine and serine, were identified and verified to enhance the rate of exfoliation of the stratum corneum. It is expected that the improvement of dullness, mild acne, fine wrinkles, and pores through skin exfoliation in the field of cosmetics can be achieved safely through these agents.
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Cosmeceuticals have biologically active ingredients and show beneficial results. However, they may not be US FDA approved. Most cosmeceuticals are made of extracts from marine algae, fruits, herbs, and other botanicals, and these ingredients may be existing already. There are a number of topical antiaging cos‐meceuticals that patients can use depending on their needs. Also known as fruit acids, alpha‐hydroxy acids (AHAs) are a group of chemical compounds that consist of a carboxylic acid substituted with a hydroxyl group on the adjacent carbon. The cosmetic and the pharmaceutical market is flooded with lightening products each claiming to be the best, but with limited clinical evidence to support their claim. Botanicals are active compounds that are isolated from plants. The potential concerns could be the lack of proper testing for efficacy. There are many false claims made, and products are highly priced.
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Hydroxy acids (HAs) represent useful substances for skin care and chemical peelings and have been used typically in concentrations ranging from 2% to 70%, depending on the indication, pH, formulation, and application schedule. The higher the concentration and the lower the pH of the product, the greater the exfoliative, epidermolytic, and even toxic and corrosive action. The most widely used hydroxy acids are glycolic, mandelic, and salicylic acids. Recently, other substances like β-lipohydroxy acids (BLHAs) and gluconolactone have been developed in order to enhance efficacy and diminish irritation. The main effects of hydroxy acids in the skin are hydration, exfoliation, acceleration of collagen synthesis and modulation of matrix degradation, epidermal turnover regulation, inhibition of tyrosinase activity, and free radical neutralization. The uses of hydroxy acids include the treatment of dry skin, hyperkeratinization, acne, rosacea and sensitive skin, hyperpigmentation, wrinkles, and photoaging, with a high tolerance and good safety profile.
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The appearance of aging skin can indeed be reversed without invasive treatments by daily skin care using scientifically proven techniques and products. Proper cleansing and exfoliation smooth the skin's surface to decrease pore size and wrinkles within days. Sun protection by application of ample amounts of high-SPF, UVA-protective, highly water-resistant sunscreen is essential to protect from photoaging and to enhance natural repair. Topical retinoids as well as topical antioxidants such as vitamins C and E, selenium, genestein, and coenzyme Q10 not only protect from but also reverse photoaging if the correct molecular forms and concentrations are applied.
Chapter
Hydroxy acids (HAs) represent useful substances for skin care and chemical peelings and have been used typically in concentrations ranging from 2 % to 70 %, depending on the indication, pH, formulation, and application schedule. The higher the concentration and the lower the pH of the product, the greater the exfoliative, epidermolytic, and even toxic and corrosive action. The most widely used hydroxy acids are glycolic, mandelic, and salicylic acids. Recently, other substances like β-lipohydroxy acids (BLHAs) and gluconolactone have been developed in order to enhance efficacy and diminish irritation. The main effects of hydroxy acids in the skin are hydration, exfoliation, acceleration of collagen synthesis and modulation of matrix degradation, epidermal turnover regulation, inhibition of tyrosinase activity, and free radical neutralization. The uses of hydroxy acids include the treatment of dry skin, hyperkeratinization, acne, rosacea and sensitive skin, hyperpigmentation, wrinkles, and photoaging, with a high tolerance and good safety profile.
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This chapter presents a basic skin regimen to protect from photodamage and to reverse the appearance of aging. The four necessary steps are cleansing, exfoliation, protection, and treatment. Proper cleansing is an essential component of skincare. The inclusion of medications as components of cleansers can be effective in actually treating the skin. Exfoliation is the rejuvenation treatment providing the most immediate improvement in appearance. The single most effective therapy for aging skin is sun protection. The ability of a sunscreen to prevent UVB‐mediated erythema is measured by the internationally accepted standard sun protection factor, the ratio of equivalent exposure by UVB in sunscreen‐protected compared with unprotected skin. Retinoids are the "gold standard" for reversing photoaging of the skin. The skin naturally uses nutritional antioxidants to protect itself from photodamage and topical application has been investigated. Ferulic acid is a potent antioxidant present in the cell walls of grains, fruits, and vegetables.
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In 1974 Van Scott and Yu first described the effects of alpha hydroxy acids (AHAs) on keratinization disorders. However, it was not until the 1990s that AHA products gained acceptance and popularity [1]. In this last decade, multiple reports showed the beneficial effects of AHAs in patients with xerosis and hyperkeratotic conditions [2-5]. As a result, AHA use by dermatologists and consumers increased dramatically. The main benefits of products containing these fruit-acid derivatives are the normalization of the keratinization process, replacement of water content, and stimulation of the epidermal cell renewal process [6].
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The current circumstance thus brings into focus a new category of desirable therapeutic and preventive agents, that is, agents that function to achieve and maintain states of optimal skin normalcy. Such a category of agents may be assigned the name of eudermaceutics, or perhaps simply topical euceutics. This group of agents would include ones to bind water and maintain optimal skin hydration; to normalize keratinization and desquamation; to enhance barrier efficiency; to reverse epidermal-dermal atrophy and maintain optimal skin morphology; and to decelerate the skin aging processes, especially those caused by oxidative damage. Candidate substances known today qualifying as topical euceutics would include water itself and adjuvant humectants; retinoids; alpha hydroxy acids (AHAs), some beta hydroxy acids (BHAs), and AHAs with multiple hydroxyl groups, poly hydroxy acids (PHAs); and sun screens to interfere with, or prevent completely, actinically induced damage that today accounts for so much skin unhealthiness.
Article
Backgroound: alpha-Hydroxy acids (AHAs) have been reported to improve aging skin. The mechanisms of action of AHAs on epidermal and dermal compartments need clarification. Objective: Our purpose was to determine the effects of AHAs on photoaged human skin by clinical and microanalytic means. Methods: Patients applied a lotion containing 25% glycolic, lactic, or citric acid to one forearm and a placebo lotion to the opposite forearm for an average of 6 months. Thickness of forearm skin was measured throughout the study. Biopsy specimens from both forearms were processed for analysis at the end of the study. Results: Treatment with AHAs caused an approximate 25% increase in skin thickness. The epidermis was thicker and papillary dermal changes included increased thickness, increased acid mucopolysaccharides, improved quality of elastic fibers, and increased density of collagen. No inflammation was evident. Conclusion: Treatment with AHAs produced significant reversal of epidermal and dermal markers of photoaging.
Article
Hyperkeratinization is a primary or fundamental event in a majority of today's skin disorders. Hyperkeratinization is usually the result of decreased desquamation due to increased corneocyte cohesion. Strength of corneocyte cohesion is determined by strength of intercellular bonding. Intercellular bonding is weakened by water and diminished by retinoids and alpha hydroxy acids (AHAs). Conversely, bonding is strengthened or enhanced by dehydration, vitamin A deficiency, and some alpha acetoxy acids (AAAs). Agents that control or modify keratinization can be useful in treatment of many skin disorders.
Article
Alpha hydroxyacids (AHAs) are used to enhance stratum corneum desquamation and improve skin appearance. The purpose of this study was to evaluate whether some AHAs improve skin barrier function and prevent skin irritation. Eleven healthy subjects (aged 28 +/- 6 years, mean +/- SD) entered the study. Six test sites of 8 x 5 cm (four different AHAs, vehicle only (VE) and untreated control (UNT) were selected and randomly rotated on the volar arm and forearm. The four different AHAs at 8% concentration in base cream were glycolic acid (GA), lactic acid, tartaric acid (TA) and gluconolactone (GLU). The products were applied twice a day for 4 weeks (2 mg/cm2). At week 4, a 5% sodium lauryl sulphate (SLS) challenge patch test was performed under occlusion for 6 h (HillTop chamber, 18 mm wide) on each site. Barrier function and skin irritation were evaluated by means of evaporimetry (Servomed EP-1) and chromametry (a* value, Minolta CR200) weekly, and at 0, 24 and 48 h after SLS patch removal. No significant differences in transepidermal water loss (TEWL) and erythema were observed between the four AHAs at week 4. After SLS challenge, GLU- and TA-treated sites resulted in significantly lower TEWL compared with VE, UNT (P < 0.01) and GA (P < 0.05) both at 24 and 48 h. Similarly, a* values were significantly reduced after irritation in GLU- and TA-treated sites. This study shows that AHAs can modulate stratum corneum barrier function and prevent skin irritation; the effect is not equal for all AHAs, being more marked for the molecules characterized by antioxidant properties.