Eudragit RL and RS Pseudolatices: Properties and Performance in Pharmaceutical Coating as a Controlled Release Membrane for Theophylline Pellets

Theophylline Active pellets were coated with Eudragit RL and RS pseudolatices in a fluidized bed. The effects of polymer ratio, additional oven drying, addition of dispersed solids, and addition of water miscible organic solvents on sustained drug release through the lates film were determined by using a modified U.S.P. Paddle dissolution method.

The release rate of theophylline can be varied by changing the polymer ratio. permeability to the drug increases with an increase in the content of Eudragit RL. Additional oven drying at 60°C for 10 hours caused no significant change in the dissolution profiles. The addition of dispersed solids such as talcum and silica resulted in an increase in drug release rate. There is no significant change in dissolution profiles when 50% methanol or acetone was added to the Eudragit RS pseudolatex.     

In-Vitro Release Kinetics of Salbutamolsulphate Microcapsules Coated with Both Eudragit Rs 100 and Eudragit RL 100

Sabutamolsulphate, a bronchodialatory drug for Asthma is encapsulated by Eudragit RS 100 and Eudragit RL 100 of varying ratios (1:1, 3:1, 1:3) using Emulsion-Solvent-Evaporation method. The experimental data obtained from the in-vitro dissolution study have been computed in the light of different kinetic models like Zero Ordr, Higuchi Matrix, First Order, Baker-Lonsdale. An extensive programming in BASIC is performed to determine the co-relation coefficient and slope for each of the functions. The diffusivity rate constant (K_BL) and diffusion coefficient (Da) have been evaluated with the help of Baker-Lonsdale Model.     

Preparation and Evaluation of Controlled Release Indomethacin Microspheres

Abstract

Microspheres containing indomethacin were prepared with various combinations of polymers Eudragit RS and Eudragit L. The effects of different ratios of polymers, solvent-polymer ratio, polymer-drug ratio and evaporation temperature on the physical characteristics of the microspheres as well as the in vitro release rate of the drug were investigated. All the factors studied had an influence on the physical characteristics of the microspheres. In vitro dissolution results showed that all formulations gave prolonged release of indomethacin and the release followed apparent zero order kinetics until 80% of drug had been released.     

Preparation and Evaluation of Controlled Release Indomethacin Microspheres

Microspheres containing indomethacin were prepared with various combinations of polymers Eudragit RS and Eudragit L. The effects of different ratios of polymers, solvent-polymer ratio, polymer-drug ratio and evaporation temperature on the physical characteristics of the microspheres as well as the in vitro release rate of the drug were investigated. All the factors studied had an influence on the physical characteristics of the microspheres. In vitro dissolution results showed that all formulations gave prolonged release of indomethacin and the release followed apparent zero order kinetics until 80% of drug had been released.     

Ketoprofen spray-dried microspheres based on Eudragit RS and RL: study of the manufacturing parameters

The preparation of ketoprofen spray-dried microspheres can be affected by the long drug recrystallization time. Polymer type and drug-polymer ratio as well as manufacturing parameters affect the preparation. The purpose of this work was to evaluate the possibility to obtain ketoprofen spray-dried microspheres using the Eudragit RS and RL; the influence of the spray-drying parameters on morphology, dimension, and physical stability of microspheres was studied. Ketoprofen microspheres based on Eudragit blend can be prepared by spray-drying and the nebulization parameters do not influence significantly particle properties; nevertheless, they can be affected by drying and storage methods. No effect of the container material is found.     

Preparation and Evaluation of Controlled Release Propranolol Hydrochloride Beads

Abstract

Conventional pan coating method was utilized to prepare propranolol-HCl sustained release coated beads. Eudragit RS 100 was used as release controlling materials. Overcoating of the beads with beeswax was also investigated. The beads were characterized for their particle size distribution, drug loading efficiency and their dissolution behaviour in 0.1N HCl, Most of the finished beads (72.4%) fall in the particle size range 800–1700 um. The actual drug content, calcu-lated as opposed to the theoretical drug content were 77.6% and 74.2% of the drug for the beads having particle size range 1700–1250 um and 1250–800 um respectively, The coating level of the polymer, the particle size of the beads and overcoating with beeswax play a major role in determining the release rate of the drug from the coated beads.     

Preparation and Evaluation of Controlled Release Propranolol Hydrochloride Beads

Conventional pan coating method was utilized to prepare propranolol-HCl sustained release coated beads. Eudragit RS 100 was used as release controlling materials. Overcoating of the beads with beeswax was also investigated. The beads were characterized for their particle size distribution, drug loading efficiency and their dissolution behaviour in 0.1N HCl, Most of the finished beads (72.4%) fall in the particle size range 800-1700 um. The actual drug content, calcu-lated as opposed to the theoretical drug content were 77.6% and 74.2% of the drug for the beads having particle size range 1700-1250 um and 1250-800 um respectively, The coating level of the polymer, the particle size of the beads and overcoating with beeswax play a major role in determining the release rate of the drug from the coated beads.     

Controlled Release Salbutamol Sulphate Molded Tablets Using Eudragit Retard

Abstract

Permeable acrylic resins were used as efficient retarding materials to prepare controlled release salbutamol sulphate molded tablets. The formulation is simple, efficient, economic and is easily shaped into molded tablets. The effects of two types of acrylic resins, namely: Eudragit RL100 ad Eudragit RS100 in concentrations 1, 2 and 5% w/w on the physical characteristics as well as on the in vitro release patterns of salbutamol sulphate from molded tablets prepared with either polyethylene glycol (PEG) 4000 or 6000 were studied. It was revealed that, as the molecular weight of the PEG increased, the hardness of the tablets increased. Considerable retardation in the drug release was observed by using Eudragit RS100 as compared to Eudragit RL100. The formulation prepared with PEG 6000 and 5% Eudragit RS100 produced much more release time prolongation than the other tested formulations. On the other hand, tablets prepared by the direct compression technique produced a faster release of salbutamol sulphate than those prepared by molding.     

Controlled Release Salbutamol Sulphate Molded Tablets Using Eudragit Retard

Permeable acrylic resins were used as efficient retarding materials to prepare controlled release salbutamol sulphate molded tablets. The formulation is simple, efficient, economic and is easily shaped into molded tablets. The effects of two types of acrylic resins, namely: Eudragit RL100 ad Eudragit RS100 in concentrations 1, 2 and 5% w/w on the physical characteristics as well as on the in vitro release patterns of salbutamol sulphate from molded tablets prepared with either polyethylene glycol (PEG) 4000 or 6000 were studied. It was revealed that, as the molecular weight of the PEG increased, the hardness of the tablets increased. Considerable retardation in the drug release was observed by using Eudragit RS100 as compared to Eudragit RL100. The formulation prepared with PEG 6000 and 5% Eudragit RS100 produced much more release time prolongation than the other tested formulations. On the other hand, tablets prepared by the direct compression technique produced a faster release of salbutamol sulphate than those prepared by molding.     

SiO2基药物可控释放材料

综述了SiO2基药物可控释放材料,分析了简单、掺杂、杂化SiO2药物可控释放凝胶,以及介孔SiO2药物可控释放材料的特点,讨论了水和前驱物的比例、催化剂、掺杂剂、凝胶前驱物的种类、凝胶比表面积与孔径、凝胶尺寸及药物负载量、以及药物与凝胶基质及掺杂剂之间的相互作用对可控释放的影响.对于SiO2基药物可控释放材料来说,基质溶胀和基质溶解对药物可控释放的影响不大,药物扩散是释放的主要机制.基于介孔SiO2的pH敏感和光敏开关效应,为SiO2基药物可控释放材料提供了新思路.     

Design and Biopharmaceutical Evaluation of Nitrofurantoin-Loaded Eudragit RS100 Micropellets

Nitrofurantoin, a synthetic bactericidal drug, was encapsulated with Eudragit RS 100 polymer by a coacervation phase separation technique using variable proportions of polyisobutylene (0% to 3%) as a protective colloid. The micropellets were evaluated by scanning electron microscopy (SEM), particle size distribution, wall thickness, and loss of wall polymer were determined. The in vitro release experiments were carried out over the entire pH range of the gastrointestinal tract, the data obtained from the dissolution profiles were compared in the light of different kinetic models, and the regression coefficients were compared. The in vivo studies were performed on female human volunteers. A linear correlation was obtained from in vitro-in vivo studies.     

Design and Biopharmaceutical Evaluation of Nitrofurantoin-Loaded Eudragit RS100 Micropellets

Nitrofurantoin, a synthetic bactericidal drug, was encapsulated with Eudragit RS 100 polymer by a coacervation phase separation technique using variable proportions of polyisobutylene (0% to 3%) as a protective colloid. The micropellets were evaluated by scanning electron microscopy (SEM), particle size distribution, wall thickness, and loss of wall polymer were determined. The in vitro release experiments were carried out over the entire pH range of the gastrointestinal tract, the data obtained from the dissolution profiles were compared in the light of different kinetic models, and the regression coefficients were compared. The in vivo studies were performed on female human volunteers. A linear correlation was obtained from in vitro–in vivo studies.     

形状记忆型水凝胶的制备及其在药物控制释放中的应用

以戊二醛为交联剂,制备了pH敏感性明胶-果胶水凝胶(GT-PT)和明胶-辛基果胶水凝胶(GT-OPT),研究了交联剂用量、温度、pH值对凝胶溶胀性能的影响及溶胀-消溶胀性能.结果表明,当温度在30～60℃时,凝胶的溶胀率随温度的升高而增大;且具有明显的pH敏感性,碱性条件下的溶胀率大于酸性条件下的溶胀率;不同pH值条件下,明胶-果胶水凝胶具有“形状记忆”功能.包埋在水凝胶中的牛血清蛋白在pH=1.0时的释药率大于pH=7.8和pH=9.18时的释药率.此类水凝胶有望用于蛋白质的pH值及温度控制释放.     

镁合金支架双重可控释放涂层的制备及药物释放性能研究

在镁合金支架材料WE42表面制备了双重可控腐蚀和药物缓释涂层,并对其药物释放性能进行了研究.DSC研究表明紫杉醇均匀分散在PLGA体系中.药物释放实验表明,PLGA可使紫杉醇长期持续释放,突释较弱,释放是由扩散-降解控制.随载药膜中PEG分子量和含量的增加,药物释放率增加.外层明胶涂层能有效降低药物释放率,延长药物释放时间.     

Design and Evaluation of Soluble Ocular Drug Insert for Controlled Release of Ciprofloxacin Hydrochloride

ABSTRACT

Purpose: Soluble ocular inserts of ciprofloxacin hydrochloride were prepared with the aim of achieving once a day administration. Design: Drug reservoir was prepared using natural hydrophilic polymer viz. gelatin while rate-controlling membrane was prepared using hydrophobic ethyl cellulose. Ocular inserts were evaluated for their physicochemical parameters like thickness, weight uniformity, drug content, percent moisture loss, and percent moisture absorption. The in vitro drug release studies were carried out using Bi-chambered donar receiver compartment model. Since targeted prolong release was observed in formulation CF2 and CF5, these formulations were further subjected to in vivo drug release study using rabbits as an animal model. In vitro drug release kinetic data was treated according to Zero, First, and Higuchi kinetics to access the mechanism of drug release. Results: Correlation between in vitro and in vivo drug release was found to be strong revealing the efficacy of the formulation. Conclusion: Formulation CF5 has achieved target of present study such as increase residence time, prolong drug release, reduction in frequency of administration, and, thus may improve the patient compliance.     

Evaluation of Spray-Drying as a Method to Prepare Microparticles for Controlled Drug Release

The possibility to obtain microcapsules or microspheres for controlled release by spray-drying is evaluated. Drugs of different solubilities like theophylline and sodium sulfamethazine, with Eudragit RS as coating polymer, are chosen.

The polymer is used, either dissolved in an hydroalcoholic solution or suspended (pseudolatex) in water, in different weight ratios with the drug. The obtained solution or suspension is spray-dried.

Scanning electron microscope analysis of the powders reveals no sign of microencapsulation. Moreover, only a fraction of the particles has a spherical shape.

For each spray-dried powder, a part of the obtained particles is compressed into tablets, and the rest is stored.

Dissolution studies in distilled water at 37 C are performed on powders and tablets.

While the uncompressed microparticles do not give any controlled release, the tablets show an ability in slowing down drug delivery greater than the one obtained with the traditional methods.     

Evaluation of Spray-Drying as a Method to Prepare Microparticles for Controlled Drug Release

The possibility to obtain microcapsules or microspheres for controlled release by spray-drying is evaluated. Drugs of different solubilities like theophylline and sodium sulfamethazine, with Eudragit RS as coating polymer, are chosen.

The polymer is used, either dissolved in an hydroalcoholic solution or suspended (pseudolatex) in water, in different weight ratios with the drug. The obtained solution or suspension is spray-dried.

Scanning electron microscope analysis of the powders reveals no sign of microencapsulation. Moreover, only a fraction of the particles has a spherical shape.

For each spray-dried powder, a part of the obtained particles is compressed into tablets, and the rest is stored.

Dissolution studies in distilled water at 37 C are performed on powders and tablets.

While the uncompressed microparticles do not give any controlled release, the tablets show an ability in slowing down drug delivery greater than the one obtained with the traditional methods.     

Preparation and in Vitro Evaluation of Controlled Release Dosage form of Indomethacin

A controlled release oral drug delivery system of Indomethacin was developed using gelatin as the matrix system, which was rigidized with different concentrations of formalin, without using alcohol. The proportion of drug and gelatin as well as the concentration of formalin had the pronounced effect on the Indomethacin release rate and the patterns of which depicted that they correlated with Lang primary requirements for drug release from controlled release dosage forms. All the types of formulations showed release rate patterns that could best be described by First Order Kinetics, indicating that First Order release was mainly operative.     

Preparation and in Vitro Evaluation of Controlled Release Dosage form of Indomethacin

Abstract

A controlled release oral drug delivery system of Indomethacin was developed using gelatin as the matrix system, which was rigidized with different concentrations of formalin, without using alcohol. The proportion of drug and gelatin as well as the concentration of formalin had the pronounced effect on the Indomethacin release rate and the patterns of which depicted that they correlated with Lang primary requirements for drug release from controlled release dosage forms. All the types of formulations showed release rate patterns that could best be described by First Order Kinetics, indicating that First Order release was mainly operative.     

复合壳层聚合物胶束的药物控制释放

通过连续原子转移自由基聚合(ATRP)合成了聚丙烯酸叔丁酯-b-聚(甲基丙烯酸二甲胺基乙酯)(PtBA-b-PDMAEMA)和聚丙烯酸叔丁酯-b-聚异丙基丙烯酰胺(PtBA-b-PNIPAM),并采用选择性溶剂自组装方法制备了具有复合壳层的核壳结构胶束(Dh=209 nm),采用动态光散射及透射电镜研究了胶束的结构和分布,进一步通过紫外光谱对胶束的药物释放性能进行了表征。研究表明,这种复合壳层的聚合物胶束会在壳层形成可控的药物通道,从而实现药物释放的精确控制。