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The Comparison of Swelling, Mucoadhesive, and Release of Ranitidine from Spherical Matrices of Alginate, Chitosan, Alginate-Chitosan, and Calcium Alginate-Chitosan
Abstract and Figures
Alginate (Alg) is a polyanionic polymer whereas chitosan (Ch) is a polycationic polymer. The purpose of this study was to compare the swelling, mucoadhesive, and release of ranitidine HCl (RH) from the spherical matrices of Alg, Ch, Alg-Ch and calcium alginate-chitosan (Ca Alg-Ch). The spherical matrices containing RH were prepared by incorporating RH with sodium Alg and/or Ch with the aid of starch mucilage to form a compact mass. This compact mass was then molded to form spherical matrices with diameter of 8.8 mm. For the preparation of Ca Alg-Ch matrices, the Alg-Ch matrices were then immersed in calcium chloride solution. The release of RH and swelling of matrices were measured by using the USP paddle method in simulated gastric fluid (SGF). RH concentrations were determined spectrophotometrically at the wavelength of 224.6 nm. The mucoadhesive force was measured in rabbits stomachs using DuNouy tensiometer. The results showed that the release of RH from Alg-Ch matrices gave the most extended release, followed by matrices of Ca Alg-Ch and then Alg matrices, while Ch matrices did not give extended release of the drug. The Higuchi plot of the release of RH from spherical matrices of Alg, Ch, Alg-Ch, and Ca Alg-Ch showed stright line with regressions coefficient (R 2) of 0.9470, 0.9638, 0.9932, and 0.9837, respectively. The drug release mechanism is anomalous or non-Fickian type. Alg-Ch matrices exhibited the greatest degree of swelling followed by Ca Alg-Ch and then Alg matrices, but Ch matrices eroded in SGF. Alg-Ch matrices showed the strongest mucoadhesive property followed by Ca Alg-Ch, Alg, and Ch matrices. It is concluded that the spherical of Alg-Ch matrices possess the highest swelling degree and mucoadhesive strength, and give the most extended of drug release in SGF than other matrices tested.
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... It is an anionic bioadhesive polymer, forming hydrogen bonds with hydroxyl group of polysaccharide chain in mucous glycoprotein and its chemical bond was non-covalent [15]. Previous study also reported the bioadhesive properties of alginate beads [16], [17]. Alginate interacts with organic diacidic base piperazine and calcium salts [18]. ...
... Then, the preparation was made as gastroretentive drug delivery system using alginate beads to increase the absorption of curcumin. Alginate beads are a mucoadhesive gastroretentive drug delivery system [16], [17]. It might be useful to prolong the residence time of preparation in the stomach so that increases the drug absorption. ...
... The mucoadhesive properties of alginate beads have been previously reported [12], [16], [17]. The mucosa lining of the stomach is rich in mucin, which contain an oligosaccharide chain with terminal sialic acid. ...
BACKGROUND: Treatment of gastric ulcer using turmeric extract is less effective because curcumin has low solubility and degraded in alkaline intestinal pH. Therefore, it is necessary to convert turmeric extract into turmeric solid dispersion to increase the dissolution of curcumin and the preparation is made in gastroretentive drug delivery system to improve the absorption of curcumin in the stomach. AIM: The aim of the study was to determine the anti-ulcer effect of gastroretentive drug delivery system of alginate beads containing turmeric extract solid dispersion compared to alginate beads containing turmeric extract (without solid dispersion) and negative control. METHODS: Turmeric powder was macerated with 96% ethanol for 8 days. The macerate was evaporated with a rotary evaporator at 50°C to obtain a concentrated extract. Turmeric extract solid dispersion was prepared by the solvent method using polyvinylpyrrolidone as a carrier. The turmeric extract solid dispersion was encapsulated with alginate gel by gelation method. The antiulcer test was performed on rats with gastric ulcer that induced by 0.6 N HCl solution. The ulcer healing was observed macroscopically and microscopically (histopathology). RESULTS: The results of observation on the treatment of rats gastric ulcer that induced by 0.6 N HCl showed the gastroretentive drug delivery system of alginate beads containing turmeric extract solid dispersion effective in healing the gastric ulcer compared to negative control. The effectiveness was statistically significantly different (p < 0.05). Alginate beads containing turmeric solid dispersion were slightly more effective than alginate beads containing turmeric extract, but the effectiveness was not statistically significant (p > 0.05). CONCLUSION: Alginate beads containing turmeric extract solid dispersion were effective in treatment of gastric ulcer in rats.
... The cross-linking process occurs when the negatively charged member of the tripolyphosphate polyanion interacts with the positively charged amine group in a complex manner [16]. were irregularly shaped and the surface of the chitosan-alginate and chitosan-alginate-calcium is smoother than the surface chitosan matrix [17]. Thus, it can be concluded that the use of chitosan as a microparticle matrix tends to produce non-spherical microparticle shapes and uneven surfaces since during the drying process the water adsorbed on the wet microparticles and pushed out. ...
Objective: The objective of this research is to investigate the effect of Hydroxypropyl Methylcellulose (HPMC) concentration as a gel base for chitosan microparticle-containing beetroot (Beta vulgaris, Linn) toward gels stability and skin brightening effect. Methods: Ionic gelation was used to make microparticle using chitosan 1% solution and beetroot dry extract as active component. Scanning Electron Microscope (SEM) and active substance loading were used for physical characterisation. The MP then was added to HPMC-based gels at 0.5, 1.0, and 1.5% w/w. Gels were tested for viscosity, pH, and active component stability. Gels were tested for skin lightening on humans. Results: Results reveal beetroot extract may be loaded into chitosan microparticle with a Drug Loading (DL) of 23.27±0.057% w/w. HPMC gels had a pH of 5-5.4 and increased viscosity related with HPMC content. Gels showed colour instability after 6 cooling-heating cycles and decreased betanin levels on day 7 at 40±2 °C and RH 75±5%. HPMC 0.5% gel brightened human skin more than other HPMC gels. Conclusion: The 0.5% HPMC gel base had the smallest betanin reduction during the accelerated stability test, compared to the 1.0 and 1.5% HPMC gels. The formulation of chitosan microparticle gel loading beetroot extract with 0.5% HPMC gel base had brightened skin better than the other two formulae.
... Another endothermic peak is prominent in the samples of the physical mix, and SFT HCQ starts before 50° and extends to around 100° (Fig. 1 b2). This can be attributed to the loss of water from hydrophilic polymers [100]. The endothermic melting peak was absent in the DSC thermogram of SFT HCQ, suggesting the possibility of the drug dissolving inside the hydrophilic carrier and conversion to an amorphous form as supported by PXRD results [35,98]. ...
Hydroxychloroquine (HCQ) was repurposed for COVID-19 treatment. Subtherapeutic HCQ lung levels and cardiac toxicity of oral HCQ were overcome by intratracheal (IT) administration of lower HCQ doses. The crosslinker-free supercritical fluid technology (SFT) produces aerogels and impregnates them with drugs in their amorphous form with efficient controlled release. Mechanistic physiologically based pharmacokinetic (PBPK) modeling can predict the lung’s epithelial lining fluid (ELF) drug levels. This study aimed to develop a novel HCQ SFT formulation for IT administration to achieve maximal ELF levels and minimal cardiac toxicity. HCQ SFT formulation was prepared and evaluated for physicochemical, in vitro release, pharmacokinetics, and cardiac toxicity. Finally, the rat HCQ ELF concentrations were predicted using PBPK modeling. HCQ was amorphous after loading into the chitosan-alginate nanoporous microparticles (22.7±7.6 μm). The formulation showed a zero-order release, with only 40% released over 30 min compared to 94% for raw HCQ. The formulation had a tapped density of 0.28 g/cm3 and a loading efficiency of 35.3±1.3%. The IT administration of SFT HCQ at 1 mg/kg resulted in 23.7-fold higher bioavailability, fourfold longer MRT, and eightfold faster absorption but lower CK-MB and LDH levels than oral raw HCQ at 4 mg/kg. The PBPK model predicted 6 h of therapeutic ELF levels for IT SFT HCQ and a 100-fold higher ELF-to-heart concentration ratio than oral HCQ. Our findings support the feasibility of lung-targeted and more effective SFT HCQ IT administration for COVID-19 compared to oral HCQ with less cardiac toxicity.
Graphical abstract
... This model is also based on Fick's diffusion law and was developed to describe the release from different porous matrices, especially for the release of poorly soluble drugs encapsulated in semi-solid or solid matrices. Moreover, according to this model, the release of active ingredients is increased with decreasing tortuosity [113]. It is possible that due to the concentrations of GEL and SA used in the encapsulation process, strong ionic interactions of the polymers occur, resulting in increased tortuosity of the hydrogels. ...
Grape pomace is a byproduct of wineries and a rich source of phenolic compounds that can exert multiple pharmacological effects when consumed and enter the intestine where they can then be absorbed. Phenolic compounds are susceptible to degradation and interaction with other food constituents during digestion, and encapsulation may be a useful technique for protecting phenolic bioactivity and controlling its release. Therefore, the behavior of phenolic-rich grape pomace extracts encapsulated by the ionic gelation method, using a natural coating (sodium alginate, gum arabic, gelatin, and chitosan), was observed during simulated digestion in vitro. The best encapsulation efficiency (69.27%) was obtained with alginate hydrogels. The physicochemical properties of the microbeads were influenced by the coatings used. Scanning electron microscopy showed that drying had the least effect on the surface area of the chitosan-coated microbeads. A structural analysis showed that the structure of the extract changed from crystalline to amorphous after encapsulation. The phenolic compounds were released from the microbeads by Fickian diffusion, which is best described by the Korsmeyer–Peppas model among the four models tested. The obtained results can be used as a predictive tool for the preparation of microbeads containing natural bioactive compounds that could be useful for the development of food supplements.
... Aliquot was transferred to 20 mL volumetric flask and adjusted the volume till the mark by using simulated gastric fluid pH 1.2 (withouth enzyme). [13] The absorbances were measured with spectrophotometer UV (Shimadzu UV-1800) under the maximum wavelength at 277 nm. The measurement result of metronidazole microcapsule preparation meet the requirements of microcapsule particle size, which is not more than 5 mm [14] 3 ...
The oral conventional metronidazole dosage forms have a short duration of action due to gastric emptying process, hence the treatment of ulcus pepticum using metronidazole become less effective. Due to retaining the dosage form in the stomach, a preparation form of sustained released drug delivery systems has been developed. The aim of this study was to developed a sustained released drug delivery systems of metronidazole using alginate and chitosan as polymers that could last longer in stomach. The formulation consisted of variatons in chitosan 0.5%, 0.75% and 1%. The drug released test was carried out using paddle method in simulated gastric medium pH 1.2 at 37°C. The dissolution test results showed that formula with 0.75% of chitosan giving the best sustained released effect and the kinetics drug realeased of microcapsule followed Higuchi order. Based on the results of the study, it can be concluded that microcapsules of metronidazole with a combination of alginate and chitosan can be prepared as sustained released formulation.
... Menurut Ton et al., (2016), bahan penyalut merupakan salah satu faktor yang mempengaruhi efisiensi enkapsulasi. Penggabungan kitosan dan STPP menyebabkan terjadi interaksi sambung silang polimer sehingga meningkatkan nilai tortuositas (Arianto et al., 2015). Tortuositas adalah besaran yang terkait dengan jalur yang dilewati oleh fluida dalam suatu medium berpori (Batys and Weroński, 2014). ...
... They possess unique physicochemical characteristics because of their reduced sizes and enhanced surface areas. CNp also finds applications in drug delivery and macromolecules whereby the active ingredients in the composition can be delivered to targeted sites (Perera and Rajapakse, 2013;Arianto et al., 2015). Furthermore, it is also useful as a carrier of antioxidants, antimicrobial agents, enzymes, minerals, and probiotics (Ojagh et al., 2010;Rajalakshmi et al., 2013). ...
Chitosan nanoparticles (CNp), nickel-chitosan nanoparticles (Ni-CNp), and copper-chitosan nanoparticles (Cu-CNp) were synthesized from pure chitosan. The samples were characterized using Energy-Dispersive X-ray Spectroscopy (EDS), Transmission Electron Microscopy (TEM), Fourier-Transform Infra-Red (FTIR), and X-ray Diffraction (XRD). Their inhibitory and bactericidal potentialities were tested against Salmonella sp. and Shigella sp. at 1000, 500, 250, and 125 mg mL⁻¹. The EDS results revealed the elemental composition of the samples. At 1000 mg mL⁻¹: against Salmonella sp., MIC values for CNp, Ni-CNp, and Cu-CNP were 20.4 ± 0.64, 25.6 ± 0.71, and 34.3 ± 0.57 mgmL⁻¹, respectively; for Shigella sp., the MIC values for CNp, Ni-CNp, and Cu-CNP were 20.8 ± 0.64, 24.2 ± 0.21, and 23.57 ± 0.58 mgmL⁻¹, respectively. This trend was also observed at 500, 250, and 125 mg mL⁻¹. The results established that the incorporation of heavy metals into CNp induced more antimicrobial potency against Salmonella sp. and Shigella sp.
... For alginate emulsions with the selected extract and essential oil were prepared with a solution of sodium alginate (DAHIPRO, 1.5 % w/v) and CaCl 2 (DAHIPRO, 1.3 % w/v) by dilution in distilled water at 35°C. Each dilution was left to stir at 200 rpm on a magnetic stirrer for 2 hours (19,20). Different emulsions were prepared by mixing clove essential oil or extract with metronidazole and alginate. ...
Objectives:The alginate microspheres were prepared
with methanol extract of rue and essential oil of
clove with metronidazole evaluating their biological
and physicochemical activities. Materials and
methods: Microspheres were evaluated with their
sphericity, encapsulation efficiency, degradation,
and release kinetics with mathematical models.
Also, their hemocompatibility and antiamebic
activity were studied on hemolytic, proteolytic, and
erythrophagocytic activities of Entamoeba histolytica.
Results: Microspheres were obtained with sphericity
equal to one, with encapsulation efficiency greater
than 50 % (except CEO in 220 nm). Their degradation
was recorded between 8 %-12 % in acidic and
basic pH. In addition, its release kinetics had a
burst constant in almost all the treatments, with the
behavior of Korsmeyer-Peppas and Peppas-Sahlin
being of pseudofickian behavior. The microspheres
were hemocompatible according to the regulations
(<10 %) and additionally decreased virulence
factors of the amoeba such as hemolytic, proteolytic,
erythrophagocytic activities. Conclusions: The
microspheres obtained could be a possible treatment
against E. histolytica. Still, other toxicity
parameters have to be determined (i.e., cytotoxicity,
cytocompatibility, biosafety, body weight, survival
rate, weight index of main organs, histopathology
of main organs, serum biochemical, etc.), as well
as physicochemical parameters such as differential
scanning calorimetry, Fourier-transform infrared
spectroscopy and viscosity.
... Penelitian terkini melaporkan, beberapa cara untuk meningkatkan kemampuan biopolimer alginat sebagai enkapsulan yakni dengan mengkompositkan dengan polimer lain seperti menggunakan kombinasi alginatmontmorillonite (Kevadiya et al., 2010), komposit alginat-kitosan dengan CaCl2 (Arianto et al., 2014), dan polietilen glikol (PEG) (Wang et al., 2007). Pemilihan polimer PEG sebagai bahan komposit dan pembuatan enkapsulan dikarenakan memiliki sifat yang baik bagi tubuh seperti biokompatibel, non-toksik, imunogenik, antigenik dan yang terpenting memiliki kelarutan yang tinggi di dalam air (Davidovich-Pinhas and Bianco-Peled., 2011). ...
p>Pengembangan penelitian tentang material berbasiskan sumber daya alam lokal dan dapat diperbaharui terus dikembangkan akhir-akhir ini. Hal tersebut didasari adanya kebutuhan material baru dengan karakteristik yang lebih menguntungkan dan dapat digunakan pada aplikasi yang spesifik. Penelitian ini bertujuan untuk mempelajari preparasi membran alginat-polietilen glikol (AP-PEG) dan aplikasinya sebagai enkapsulan. Alginat yang digunakan adalah hasil ekstraksi dari rumput laut cokelat Padina sp. Dengan metode maserasi jalur asam alginat. Preparasi membrane alginat Padina sp. -polietilen glikol (AP-PEG) dilakukan dengan perbandingan PEG-AP = 1:5; 1:10; 1:15; 0:1 (b/b). Analisis gugus fungsi terhadap seluruh membran yang dihasilkan, menunjukkan bahwa membran AP-PEG yang dihasilkan diprediksi sebagai hasil blending secara fisika karena tidak ada gugus fungsi baru yang terbentuk. Membran dengan perbandingan berat PEG-AP=1:15 memiliki karakteristik terbaik dengan persentase swelling sebesar 1465,5%, stress sebesar 14,588 MPa, strain 0,07 dan Modulus Young sebesar 193,13 MPa. Hasil analisis morfologi menunjukkan bahwa banyak rongga ditemukan pada membrane tersebut. Hasil uji disolusi terhadap membrane tersebut menunjukkan bahwa, pada pH 1,2 membran tersebut dapat melepaskan vitamin C sebesar 78,12% selama 60 menit dan tidak mengalami cracking . Di sisi lain, pada pH 7,2 membran tersebut dapat melepaskan vitamin C sebesar 83,54% dan cracking terjadi dalam waktu 12 menit. Hasil penelitian ini menunjukkan bahwa komposit AP-PEG dapat dibuat dari rumput laut coklat dan memiliki kemampuan sebagai enkapsulan.
Alginate Padina sp. - Polyethylene Glycol (AP - PEG) Membranes: Preparation, Characterization and Their Application as Encapsulant . The development of research on materials based on local and renewable natural resources has been continuously being developed recently. This is based on the need for new materials with more favorable characteristics and can be used in specific applications. This research aims to study the synthesis of alginate-polyethylene glycol (AP-PEG) membranes and their application as an encapsulant. The alginate was extracted from the brown seaweed Padina sp . by maceration method using alginic acid pathway. Alginate Padina sp. -polyethylene glycol (AP-PEG) alginate membrane was prepared with a ratio of PEG:AP = 1: 5, 1:10, 1:15 and 0:1 (w/w). The functional group analysis showed that the resulting AP-PEG membranes were predicted as a result of physical blending due to no new functional groups are formed. The membrane with a weight ratio of PEG:AP = 1:15 had the best characteristics, with a percentage of swelling of 1465.5%, stress of 14.588 MPa, 0.07 strain, and Young Modulus of 193.13 MPa. Morphological analysis showed that the membrane obtained had many cavities. The dissolution test showed that the AP-PEG membrane was able to release vitamin C of 78.12% for 60 minutes at pH 1.2 and no cracking was observed, while at pH 7.2 the membrane was able to distribute vitamin C by 83.54% and cracking occurs within 12 minutes. The results of this study indicate that AP-PEG composites can be made from brown seaweed and have good encapsulant capabilities.
... jiwa penduduk) (Kurnia, 2011), maka penatalaksanaan terapi ulkus lambung terkini harus digali dengan metode yang efektif dan efisien dengan penggunaan bahan alam sebagai sumber obat dan sebagai obat. Penelitian sebelumnya menunjukkan pemberian 1 mL sirup dapat menyembuhkan ulkus lambung tikus yang diinduksi dengan aspirin 400 mg/kgbb tikus (Arianto et al., 2014) dan pemberian fukoidan kepada pasien di Unit Endoskopi Rumah Sakit Cipto Mangunkusumo dapat menambah ketebalan mukus mukosa lambung pada pasien gastritis kronik (Renaldi et al., 2011). ...
Tujuan penelitian untuk mengetahui efek antiulkus isolat fukoidan dan Sargassum polycystum terhadap tikus putih jantan. Sampel terdiri dari 45 ekor tikus jantan dibagi 9 kelompok yaitu normal, CMC-Na, sukralfat, fukoidan dan 25mg/kgbb, 50mg/kgbb dan 100mg/kgbb. Perlakuan diberi per oral selama 10 hari. Pada hari ke-10, tikus dipuasakan selama 24 jam dan diberikan induksi etanol P.A. Kemudian tikus dikorbankan dan diambil lambung untuk dilakukan pemeriksaan makroskopik dan mikroskop. Hasil pemeriksaan karakteristik simplisia Sargassum polycystum diperoleh kadar air 9,05%, susut pengeringan 8,74% dan rendemen hasil isolasi fukoidan dan adalah 4,01% dan 6,4%. Hasil identifikasi fukoidan secara spektrofotometri FTIR menunjukkan bentuk spektrum dan kurva serapan identik dengan baku pembanding fukoidan. Persentase jumlah tukak masing-masing dosis fukoidan dan yaitu, dosis 25mg/kgbb (1.04 dan 0,85), dosis 50mg/kgbb (0,84 dan 0,67), dosis 100mg/kgbb (0,21 dan 0,40). Kesimpulan hasil penelitian adalah isolat fukoidan dan memiliki efek gastroprotektif terhadap lambung tikus putih dengan dosis optimum 100mg/kgbb.
The objective of this paper is to discuss the potential of sodium alginate as a biopolymer in the formulation development and its allied applications. There is a growing trend in pharmaceutical in food industry to avoid the harsh condition in the preparation for administration to the body or for the storage purpose as it induce the side effects, instability or loss of therapeutic effect of the medicament. The sodium alginate is a versatile functional biomaterial for viscosity enhancement, stabilizer, matrixing agent, encapsulation polymer, bioadhesive and film former in transdermal and transmucosal drug delivery. The present article reviews sources, preparation, properties, crosslinking methodology, compendial standards, methods utilized for preparation of drug delivery systems using sodium alginate and its potential applications.
The objective of this article is to review the spectrum of mathematical models that have been developed to describe drug release from hydroxypropyl methylcellulose (HPMC)-based pharmaceutical devices. The major advantages of these models are: (i) the elucidation of the underlying mass transport mechanisms: and (ii) the possibility to predict the effect of the device design parameters (e.g., shape, size and composition of HPMC-based matrix tablets) on the resulting drug release rate, thus facilitating the development of new pharmaceutical products. Simple empirical or semi-empirical models such as the classical Higuchi equation and the so-called power law, as well as more complex mechanistic theories that consider diffusion, swelling and dissolution processes simultaneously are presented, and their advantages and limitations are discussed. Various examples of practical applications to experimental drug release data are given. The choice of the appropriate mathematical model when developing new pharmaceutical products or elucidating drug release mechanisms strongly depends on the desired or required predictive ability and accuracy of the model. In many cases, the use of a simple empirical or semi-empirical model is fully sufficient. However, when reliable, detailed information are required, more complex, mechanistic theories must be applied. The present article is a comprehensive review of the current state of the art of mathematical modeling drug release from HPMC-based delivery systems and discusses the crucial points of the most important theories. (C) 2012 Published by Elsevier B.V.
Bioadhesive drug delivery systems (BDDSs) could improve bioavailability by protecting bioactive molecules from physical and chemical degradation, enhancing absorption rates by minimizing diffusion barriers, and increasing the period for absorption by prolonging residence time. The in vivo bioadhesive performance of calcium alginate microspheres and poly(fumaric-co-sebacic anhydride) 20:80 microspheres were evaluated in two ways. Firstly, effect on GI transit was measured in rats. P(FA:SA) 20:80 microspheres showed significantly prolonged retention in the gut when compared to alginate microspheres. Secondly, the ability of these polymers to improve relative bioavailability of a model drug, dicumarol, in rats was assayed. A significant increase was measured in the area under the plasma concentration-time curve for dicumarol encapsulated in P(FA:SA) 20:80 when compared to its controls. The results of this study suggest that polymers which have been shown to produce strong bioadhesive forces in vitro and delayed GI transit in vivo may be used to improve oral bioavailability of certain drugs.
A range of commercial chitosans were sourced, subjected to controlled acid hydrolysis, and their molecular size profiles and degrees of acetylation (DA) determined (pre- and post-hydrolysis) by High Performance Size Exclusion Chromatography and 1H-NMR spectroscopy, respectively. Unhydrolysed and hydrolysed chitosans were subsequently utilised for modification of sodium alginate/alginic acid fibres (prepared using a range of different fibre spinning conditions), and levels of chitosan incorporated onto/into base alginate fibres were estimated by elemental analysis. Tensile properties (% elongation and tenacity) of resultant chitosan/alginate fibres were determined in order to assess their suitability for potential application in wound dressings. A broad range of chitosan contents (∼0–6% w/w) and hydrolysed chitosan contents (∼7–25% w/w) were obtained using a variety of alginate and chitosan starting materials. Modification of fibres with unhydrolysed chitosans generally resulted in a significant reduction in tenacity (and a reduction in % elongation if a water washing stage was not used), i.e. no increase in fibre strength was observed, implying that the unhydrolysed chitosan is more like a coating rather than penetrating/reinforcing the alginate fibre. Reduction of chitosan molecular weight had a positive effect on its ability to penetrate the alginate fibres, not only increasing fibre chitosan content, but also reinforcing fibre structure and thus enhancing tensile properties (compared with unhydrolysed chitosan/alginate fibres). Hydrolysed chitosan/alginate fibres demonstrated an antibacterial effect (in terms of bacterial reduction) with initial use, and had the ability to provide a slow release/leaching of antibacterially active components (presumably hydrolysed chitosan fragments). The overall aims of maximising chitosan content (in order to provide satisfactory antibacterial activity) whilst retaining desirable physical properties (i.e. satisfactory textile processing ability) were therefore achieved, with respect to the fibres having potential application as wound dressing materials.
Purpose: The aim of this work was to prepare nimodipine-loaded alginate-chitosan beads for sustained drug release. Methods: Nimodipine-loaded alginate-chitosan beads were prepared by ionic gelation method using various combinations of chitosan and Ca2+ as cations and alginate as anion. The swelling ability and in vitro drug release characteristics of the beads were studied at pH 1.2 and 6.8. Infra-red (IR) spectrometry, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), x-ray diffraction (XRD), and atomic absorption spectroscopy (AAS) were also applied to investigate the physicochemical characteristics of the drug in bead formulations. Results: The surface morphology, size, and drug loading of the beads varied with increase in the concentration of chitosan and calcium chloride in the gelation medium. The swelling ability of the beads in different pH media was dependent on the presence of a polyelectrolyte complex in the beads and the pH of the media. Both calcium alginate beads and the beads treated with chitosan failed to release the drug at pH 1.2 over the period of study. On the other hand, at pH 6.8, calcium alginate beads released approx. 96 % of drug in 6 h, but treatment of the beads with chitosan lowered drug release to 73 %. Drug release mechanism was either "anomalous transport" or "case-II transport". Data from characterisation studies indicate that there was no significant change in the physical state of the drug in the bead formulations. Conclusion: Although nimodipine-loaded alginate beads showed poor sustained release characteristics, modification with chitosan yielded beads that exhibited sustained drug release.
Membran kompleks polielektrolit alginat-kitosan dapat dibuat melalui pencampuran larutan natrium alginat dan kitosan pada pH 5,28. Membran yang dihasilkan dikarakterisasi sifat difusinya terhadap urea, natrium salisilat dan albumin, SEM, uji pengembangan, uji tarik serta analisis spektroskopi FT-IR nya. Urea dan natrium salisilat dapat melewati membran, sementara albumin sama sekali tidak dapat melewati membran tersebut. Hasil penelitian menunjukkan bahwa pada saat waktu difusi 180 menit, sifat difusi membran alginat-kitosan terhadap zat dengan berat molekul yang berbeda adalah: untuk urea sebesar 460,529 mcg/ml, untuk Na salisilat sebesar 25,658 mcg/ml sedangkan untuk albumin 0 mcg/ml (tidak terdifusi). Hasil analisis spektroskopi FT-IR menunjukkan bahwa tidak terjadi reaksi antara alginat dengan kitosan akan tetapi hanya interaksi. Berdasarkan penelitian ini, membran kitosan-alginat berpotensi untuk digunakan sebagai membran hemodialisa. skm-jan2006- (3)
Bovine serum albumin-loaded beads were prepared by ionotropic gelation of alginate with calcium chloride and chitosan. The effect of sodium alginate concentration and chitosan concentration on the particle size and loading efficacy was studied. The diameter of the beads formed is dependent on the size of the needle used. The optimum condition for preparation alginate-chitosan beads was alginate concentration of 3% and chitosan concentration of 0.25% at pH 5. The resulting bead formulation had a loading efficacy of 98.5% and average size of 1,501 mum, and scanning electron microscopy images showed spherical and smooth particles. Chitosan concentration significantly influenced particle size and encapsulation efficiency of chitosan-alginate beads (p < 0.05). Decreasing the alginate concentration resulted in an increased release of albumin in acidic media. The rapid dissolution of chitosan-alginate matrices in the higher pH resulted in burst release of protein drug.
Drug treatment of gastrointestinal diseases, which was previously limited to the use of antacids, anticholinergics, antispasmodics, cathartics and laxatives, has changed markedly over the past decade. Histamine H2-receptor antagonists (e.g. cimetidine, ranitidine and more recently famotidine and nizatidine) have revolutionised the treatment of peptic acid disorders, but their role is currently challenged by muscarinic-M1-receptor antagonists (e.g. pirenzepine), proton pump inhibitors (e.g. omeprazole), prostaglandin analogues and site-protective drugs (e.g. colloidal bismuth subcitrate and sucralfate). Newer anti-emetics with prokinetic properties (e.g. metoclopramide, domperidone and cisapride) have also been introduced in the management of gastrointestinal motility disturbances, and new anti-inflammatory salicylates (e.g. olsalazine and mesalazine) have been developed for the treatment of chronic inflammatory bowel diseases. Finally, diphenoxylate and loperamide have gained wide clinical application as nonspecific antidiarrhoeal agents. The basic pharmacokinetic properties of the above agents are briefly reviewed with the main emphasis on the newer and more important drugs in current use. Furthermore, the effects of age and disease on pharmacokinetics, in addition to drug interaction potentials and pharmacokinetic-pharmacodynamic relationships, are discussed.
The anti-inflammatory salicylates, nonspecific antidiarrhoeal agents, laxatives and cathartics will be dealt with in Part II.
Part I of this article, which appeared in the previous issue of the Journal, covered the following agents: histamine H2-receptor antagonists (cimetidine, ranitidine, famotidine, nizatidine); muscarinic-M1-receptor antagonists (pirenzepine); proton pump inhibitors (omeprazole); site-protective agents (colloidal bismuth subcitrate, sucralfate); antacids and prostaglandin analogues; antiemetics and prokinetics (metoclopramide, domperidone, cisapride); and antispasmodics. In Part II, we consider the anti-inflammatory salicylates, nonspecific antidiarrhoeal agents, laxatives and cathartics.