In vitro evaluation of commercially available theophylline sustained release tablets in Pakistan

The dissolution behavior of five commercially available brands of sustained release theophylline tablets was studied in phosphate buffer solutions of pH 1.2, 4.5, 5.5, 6.0 and 7.5 at 37 °C using the USP dissolution apparatus II (paddle method). Drug concentration in the samples was determined spectrophotometrically at 272 nm. For predicting the release characteristics of theophylline from selected commercially available tablets the data obtained in the dissolution studies was fitted into various mathematic models defining kinetic parameters of drug release like zero-order rate equation, first-order rate equation, Hixen-crowell cube root law, Higuchi equation and Korsemeyer-Peppas model. Tablets were subjected to weight variation test, hardness, drug content and in vitro release studies. The present study revealed that drug release increases with the increase of pH of the dissolution medium and also varies from brand to brand. Among the five selected brands, B1 and B4 showed better pH dependency and drug release behaviour. It has been suggested that possible reasons for difference in dissolution or drug release behaviour are the difference in the manufacturing techniques and the quantity of hydrophobic excepients used by different manufacturers, which retard the penetration of dissolution medium and ultimately decreases availability of drug in the solution.Colegio de Farmacéuticos de la Provincia de Buenos Aire

In vitro evaluation of commercially available theophylline sustained release tablets in Pakistan

The dissolution behavior of five commercially available brands of sustained release theophylline tablets was studied in phosphate buffer solutions of pH 1.2, 4.5, 5.5, 6.0 and 7.5 at 37 °C using the USP dissolution apparatus II (paddle method). Drug concentration in the samples was determined spectrophotometrically at 272 nm. For predicting the release characteristics of theophylline from selected commercially available tablets the data obtained in the dissolution studies was fitted into various mathematic models defining kinetic parameters of drug release like zero-order rate equation, first-order rate equation, Hixen-crowell cube root law, Higuchi equation and Korsemeyer-Peppas model. Tablets were subjected to weight variation test, hardness, drug content and in vitro release studies. The present study revealed that drug release increases with the increase of pH of the dissolution medium and also varies from brand to brand. Among the five selected brands, B1 and B4 showed better pH dependency and drug release behaviour. It has been suggested that possible reasons for difference in dissolution or drug release behaviour are the difference in the manufacturing techniques and the quantity of hydrophobic excepients used by different manufacturers, which retard the penetration of dissolution medium and ultimately decreases availability of drug in the solution.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Effect of Different Hydrophillic Binders on the Dissolution Profiles of Mefenamic Acid

The aim of this study was to elaborate the effect of hydrophilic binders on the release profiles of matrix tablets containing mefenamic acid. Mefenamic acid tablets were prepared using wet granulation method. The investigated hydrophilic binders included starch, pectin, tragacanth and honey. It was found that there was a decrease in the percentage of drug release with the increase in the binder (except tragacanth) concentration, i.e. sustained release behavior was obtained. Zero order model was best fit to all dissolution profiles (indicating controlled release behavior) except that of honey based formulations which followed Higuchi kinetics. It can be concluded from all above stated results that pectin might be considered as a good binder for the tablet formulation of mefenamic acid as compared to lactose as a standard one. Hence the present study justifies the use of pectin as substitute of starch as a binder.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Development and release kinetics of a novel formulation of nimesulide prepared by microencapsulation using synthetic polymers

The synthetic polymers and their combinations were employed to retard the release of nimesulide from microcapsules. Microcapsules were prepared in different ratios of Eudragit RL 100 and hydroxy propyl methyl cellulose (HPMC) separately and in combination. All formulations of microcapsules were compressed to tablets. Dissolution of microcapsules and their tablets was performed by USP-apparatus-II in 900 mL borate buffer of pH 8.4 at 37.0 ± 0.5 ºC, at 50 rpm. In vitro kinetics was determined by various models including Zero order, First Order, Higuchi, Korsmeyer-Peppas and Hixson-Crowell. Eudragit showed higher retarding effect over extended period of time on release of drug than HPMC alone or its combination with Eudragit.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Assessment of Palmitoyl and Sulphate Conjugated Glycol Chitosan for Development of Polymeric Micelles

Introduction: Amphiphilic copolymers are capable of forming core shell-like structures at the critical micellar concentration (CMC); hence, they can serve as drug carriers. Thus, in the present work, polymeric micelles based on novel chitosan derivative were synthesized. Methods: Block copolymer of palmitoyl glycol chitosan sulfate (PGCS) was prepared by grafting palmitoyl and sulfate groups serving as hydrophobic and hydrophilic fractions, respectively. Then, fourier transform infrared spectra (FTIR) and spectral changes in iodine/iodide mixture were carried out. Results: FTIR studies confirmed the formation of palmitoyl glycol chitosan sulfate (PGCS) and spectral changes in iodine/iodide mixture indicated CMC which lies in the range of 0.003-0.2 mg/ml. Conclusion: Therefore, our study indicated that polymeric micelles based on palmitoyl glycol chitosan sulphate could be used as a prospective carrier for water insoluble drugs