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RUíZ,Gloria; GHALY,Evone S.;
Vitae , 2006,
Abstract: the objective of this research is a bioadhesive two layers controlled release tablets. the drug release and the physical properties of tablet formulations using two polymers (carrageenan 934 and eudragit rl po) at three levels and at a combination of different ratios of the two polymers were evaluated. formulation containing 40% total polymer level and a ratio of 1 carrageenan to 1 eudragit rlpo was the best formulationa. this formulation was tested in different dissolution medium and at different rotational speed. the drug release was 96.3% in phosphate buffer ph 7.4; 59.1% in 0.1 n hcl and 46.4% in distilled water. this study demonstrates the significance of the combination of two polymers for obtaining controlled release bioadhesive matrix and enhancing the characteristic of each polymer.
Gloria RUíZ,Evone S. GHALY
Vitae , 2006,
Abstract: El objetivo de esta investigación es desarrollar una tableta de dos capas bioadhesive de liberación controlada. El comportamiento de la liberación de la droga y las propiedades físicas de las formulaciones de las tabletas usando dos polímeros (Carrageenan 934 y Eudragit RLPO) a tres niveles y a diferentes razones, a un nivel total de polímero de 40% p/p fueron comparados. Las formulaciones con dos polímeros a un nivel de 40% controlaron la liberación de la droga mejor que las que contenían un polímero. Las tabletas a razón (1:1) liberaron 46.4% mientras que las formulaciones a razones 3:1 y 1:3 liberaron 58.9% y 72.9%. La formulación con razón (1:1) fue seleccionada la mejor y probada para la disolución en HCl 0.1N y una solución amortiguadora de fosfato a pH 7.4 en adición a agua destilada. La liberación de la droga en la solución amortiguadora fue 96.3%, en HCl y agua destilada fue 59.1% y 46.4 %. Este estudio demuestra la importancia del uso de la combinación de polímeros para obtener una matriz bioadhesiva de liberación controlada y realzar las características de cada polímero. The objective of this research is a bioadhesive two layers controlled release tablets. The drug release and the physical properties of tablet formulations using two polymers (Carrageenan 934 and Eudragit RL PO) at three levels and at a combination of different ratios of the two polymers were evaluated. Formulation containing 40% total polymer level and a ratio of 1 Carrageenan to 1 Eudragit RLPO was the best formulationa. This formulation was tested in different dissolution medium and at different rotational speed. The drug release was 96.3% in phosphate buffer pH 7.4; 59.1% in 0.1 N HCl and 46.4% in distilled water. This study demonstrates the significance of the combination of two polymers for obtaining controlled release bioadhesive matrix and enhancing the characteristic of each polymer.
Evaluation of Natural Exudate Gum from Sterculia urens as Gelling Agent in Culture Media for In vitro Regeneration of Rough Lemon (Citrus jambhiri Lush.) Shoot Tips
Balwinder Singh,Amritpal Kaur,Jaspreet Singh
Journal of Biological Sciences , 2011,
Abstract: Natural exudate gum (sterculia gum) has been successfully used as gelling agent in culture media with an aim to reduce the production cost of tissue culture raised plants. Shoot tips were cultured on agar and sterculia gum gelled media to study the difference in shoot and root regeneration response. Initially, shoot tips were cultured on agar gelled Murashige and Skoog (MS) medium supplemented with different concentrations of 6-Benzyl amino purine (BAP), Kinetin (KN) and Naphthalene acetic acid (NAA). Maximum percentage of cultures showing shoot regeneration (63.19%) was observed on agar gelled MS medium containing BAP 1.5, KN 0.5 and NAA 0.5 mg L-1. Sterculia gum and agar were then evaluated at different concentrations and combinations. The media gelled with sterculia gum was equally transparent as that of liquid medium. The shoot regeneration response on media gelled with 25 and 30 g L-1 sterculia gum were 49.99 and 61.11% respectively. Regenerated shoots were rooted on agar gelled MS medium supplemented with different concentrations of Indole-3-Acetic Acid (IAA), NAA and Indole -3-butyric acid (IBA, 0.5-2.5 mg L-1). Maximum rooting response (56.94%) was observed with IBA 2.0 mg L-1. Same medium when evaluated for rooting response using sterculia gum (30 g L-1) as gelling agent, 56.24% cultures showed root regeneration. The difference in regeneration response obtained with agar (8 g L-1) and sterculia gum (30 g L-1) was statistically insignificant. This study indicates that sterculia gum can be used as alternative gelling agent in place of agar for the development of cost effective micropropagation protocol.
High encapsulation efficiency of sodium alendronate in eudragit S100/HPMC blend microparticles
Cruz, Letícia;Assump??o, Evelise;Guterres, Sílvia Stanis?uaski;Pohlmann, Adriana Raffin;
Química Nova , 2009, DOI: 10.1590/S0100-40422009000500016
Abstract: the hydrophilic drug sodium alendronate was encapsulated in blended microparticles of eudragit? s100 and methocel? f4m or methocel? k100lv. both formulations prepared by spray-drying showed spherical collapsed shape and smooth surface, encapsulation efficiencies of 85 and 82% and mean diameters of 11.7 and 8.4 μm, respectively. at ph 1.2, in vitro dissolution studies showed good gastro-resistance for both formulations. at ph 6.8, the sodium alendronate release from the microparticles was delayed and was controlled by fickian diffusion. in conclusion, the prepared microparticles showed high encapsulation efficiency of sodium alendronate presenting gastro-resistance and sustained release suitable for its oral administration.
Kamlesh J Wadher*,Rajendra B Kakde,Milind J Umekar
Pharmacie Globale : International Journal of Comprehensive Pharmacy , 2011,
Abstract: Metformin hydrochloride has relatively short plasma half life, low absolute bioavailability. The need for the administration two to three times a day when larger doses are required can decrease patient compliance. Sustained release formulations that would maintain plasma level for 8-12 h might be sufficient for daily dosing of meformin. The overall objective of the present work was to develop an oral sustained release metformin tablet prepared by direct compression method, using hydrophilic Eudragit RSPO and RLPO alone or in combination with hydrophobic ethyl cellulose polymer as rate controlling factor. All the batches were evaluated for thickness, weight variation, hardness, and drug content uniformity and in vitro drug release. Mean dissolution time is used to characterize drug release rate from a dosage form and indicates the drug release retarding efficiency of polymer. When Eudragit RSPO and RLPO were used alone as the only retarding polymer, a sustained drug release pattern were not observed while, Inclusion of ethylcellulose in the matrix almost doubled (12 h) the time required for releasing the drug. Kinetic modeling of in vitro dissolution profiles revealed the drug release mechanism ranges from diffusion controlled to anomalous type. Fitting the data to Korsmeyer equation indicated that diffusion along with erosion could be the mechanism of drug release.
Formulation Development and Evaluation of Drug Release Kinetics from Colon-Targeted Ibuprofen Tablets Based on Eudragit RL 100-Chitosan Interpolyelectrolyte Complexes  [PDF]
Kenneth Chibuzor Ofokansi,Franklin Chimaobi Kenechukwu
ISRN Pharmaceutics , 2013, DOI: 10.1155/2013/838403
Abstract: Colon-targeted drug delivery systems (CTDDSs) could be useful for local treatment of inflammatory bowel diseases (IBDs). In this study, various interpolyelectrolyte complexes (IPECs), formed between Eudragit RL100 (EL) and chitosan (CS), by nonstoichiometric method, and tablets based on the IPECs, prepared by wet granulation, were evaluated as potential oral CTDDSs for ibuprofen (IBF). Results obtained showed that the tablets conformed to compendial requirements for acceptance and that CS and EL formed IPECs that showed pH-dependent swelling properties and prolonged the in vitro release of IBF from the tablets in the following descending order: 3?:?2?>?2?:?3?>?1?:?1 ratios of CS and EL. An electrostatic interaction between the carbonyl (–CO–) group of EL and amino (– ) group of CS of the tablets formulated with the IPECs was capable of preventing drug release in the stomach and small intestine and helped in delivering the drug to the colon. Kinetic analysis of drug release profiles showed that the systems predominantly released IBF in a zero-order manner. IPECs based on CS and EL could be exploited successfully for colon-targeted delivery of IBF in the treatment of IBDs. 1. Introduction In recent years, various strategies have been adopted for specific drug delivery to well-defined sites of the gastrointestinal (GI) tract, the colon being the most important one [1–5]. Enteric polymers are used for this purpose, as they are able to release the drug at a particular pH. The pH-sensitive copolymers, such as methacrylic acid/methyl methacrylate copolymers and Eudragit types L and S, dissolve in aqueous media at pH 6 and 7, respectively, which may be equivalent to drug release in the distal ileum [6]. Similarly, chitosan-based polyelectrolyte complexes have been employed as potential carrier materials in drug delivery systems [7]. Furthermore, a growing interest in polyelectrolyte complexes has led to the formulation and characterization of systems involving a variety of anionic and cationic polymers: Eudragit L 30 D-55 and gelatin [8], Eudragit L 100-Eudragit S 100 [9], Eudragit E-Eudragit L [10, 11], Eudragit E-sodium alginate [12], chitosan-alginate/chitosan-carrageenan (mainly kappa-carrageenan with low amounts of lambda-carrageenan) [13], chitosan-polygalacturonic acid [14], chitosan-carboxymethylcellulose [15], and chitosan-alginate [16]. Conventional drug delivery is unfavourable to special cases where drug targeting is applied, that is, when avoidance of gastric dissolution or targeting to the colon is desirable. Colon-targeted drug delivery differs
Mechanical Reinforcement of Wool Fiber through Polyelectrolyte Complexation with Chitosan and Gellan Gum  [PDF]
Khairul Anuar Mat Amin,Marc in het Panhuis
Fibers , 2013, DOI: 10.3390/fib1030047
Abstract: The formation of polyelectrolyte complex (PEC) wool fibers formed by dipping chitosan or gellan gum-treated wool fibers into biopolymer solutions of opposite charge is reported. Treating wool fibers with chitosan (CH) and gellan gum (GG) solutions containing food dyes resulted in improved mechanical characteristics compared to wool fibers. In contrast, pH modification of the solutions resulted in the opposite effect. The mechanical characteristics of PEC-treated fibers were affected by the order of addition, i.e., dipping GG-treated fibers into chitosan resulted in mechanical reinforcement, whereas the reverse-order process did not.
M Sivabalan*,Anto Shering,Anup Jose,G Nigila
Pharmacie Globale : International Journal of Comprehensive Pharmacy , 2011,
Abstract: The goal of the present investigation was to formulate and evaluate chitosan and Eudragit nanoparticles of 5- Fluorouracil for cancer therapy. Nanoparticles of 5- Fluorouracil were prepared using chitosan , Eudragit S 100, liquid paraffin and Tween -20 using Emulsion droplet coalescence method. The concentration of the polymers Chitosan and Eudragit S 100 were selected based on the results on preliminary screening. The nanoparticles prepared were evaluated for morphology, loading efficiency, invitro release and invitro anticancer activities. The particle shape and morphology of the prepared 5-Fluorouracil nanoparticles were determined by SEM analysis. The amount of 5-Fluorouracil entrapment in the nanoparticles was calculated by the difference between the total amount of drug added to the nanoparticle and the amount of non entrapped drug remaining in the aqueous supernatant. A franz diffusion cell was used to monitor 5-Fluorouracil release from the nanoparticles. The in-vitro anticancer activity of formulated nanoparticles was carried out in Dalton-Lymphoma ascites (DLA) cells bearing mice. The formulations CF1, CF2, EF2 and EF3 showed good drug release from the polymer. The percentage cumulative drug release after 12 hours was 74.49, 74.06, 77.68 and 75.51% respectively. However about 15% initial burst release was found at 1 hour in all formulations. EF2 released 77.68% of 5- Fluorouracil in 12 hours with a burst drug release nearly 14.92% of drug within the initial 1 hour. Formulations 4 out of 9 showed good drug release from the polymer, the percentage cumulative drug release after 12 hours were in the range of 74-78 %. Among the four formulations EF 2 (1% Chitosan & 1.5 % Eudragit S 100) showed maximum drug release in 12 hours diffusion study and good entrapment efficiency. In-vitro anticancer study revealed that the formulated nanoparticles were found to have good cidal activity on cancer cells in sustained manner.
Nutritional Evaluation of Sterculia setigera Seeds and Pod
M. Idu,S. Uzoekwe,H.I. Onyibe
Pakistan Journal of Biological Sciences , 2008,
Abstract: The results obtained on analysis of the seeds and pods of Sterculia setigera for their nutritional composition revealed that while the seed sample has high crude protein, crude fibre, carbohydrate and fat contents, their contents in the pod sample was very low. The analysis of the mineral profile reveals that the seed of Sterculia setigera is rich in sodium, iron, zinc and manganese. Conversely, the mineral composition of the pod is low.
Tres nuevas especies de Sterculia L. (Sterculiaceae) de Venezuela Three new species of Sterculia L. (Sterculiaceae) of Venezuela
Acta Botánica Venezuelica , 2005,
Abstract: Como resultado del estudio taxonómico del género Sterculia L. (Sterculiaceae) en Venezuela, se describen tres nuevas especies: Sterculia abbreviata, procedente de los estados Amazonas, Aragua, Delta Amacuro, Mérida y Miranda; S. amazonica, a lo largo del Río Ocamo del estado Amazonas, y estado Bolívar; S. steyermarkii, en bosques siempreverdes en las costas del estado Miranda y en el estado Mérida. As a result of a taxonomical study of the genus Sterculia L. (Sterculiaceae) in Venezuela, three new species were described: Sterculia abbreviata collected in Aragua, Amazonas, Delta Amacuro, Merida and Miranda states; S. amazonica along the Ocamo River (Amazonas State) and Bolivar State; S. steyermarkii from evergreen forest along the Miranda coast and Merida State.
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