Comparative evaluation of carbamazepine release from single and bi-polymeric based matrices

In the present study the release rate and kinetics of  carbamazepine as a model drug from various single and bi-polymeric matrices were studied. Matrices containing different percentages of hydroxylpropyl methylcellulose (HPMC), ethylcellulose (EC), Eudragit RS (EuRS) or various ratios of polymer blends based on HPMC were prepared. In vitro release studies were carried out in 1% sodium lauryl sulphate (SLS) aqueous solution. Mean dissolution times (MDT) were calculated and the release kinetics were evaluated using different mathematical models. The results showed that carbamazepine release was sustained in the presence of 15% HPMC for 6 hrs, but increasing the polymer content had no obvious effect. Application of EC or EuRS both in the percentages of 20% and 25% had more influence in retarding drug release rate (MDTs about 6 hrs). The results for bi-polymeric matrices revealed that overall, adding EC or EuRS as inert polymers to HPMC matrices resulted in a noticeable reduction in carbamazepine release rate compared to single polymer based matrices. Application of bi-polymeric matrices could be considered as a suitable approach for delivering the drug in a prolonged manner

Multiunit Floating Drug Delivery System of Rosiglitazone Maleate: Development, Characterization, Statistical Optimization of Drug Release and In Vivo Evaluation

A multiunit floating drug delivery system of rosiglitazone maleate has been developed by encapsulating the drug into Eudragit® RS100 through nonaqueous emulsification/solvent evaporation method. The in vitro performances of microspheres were evaluated by yield (%), particle size analysis, drug entrapment efficiency, in vitro floating behavior, surface topography, drug–polymer compatibility, crystallinity of the drug in the microspheres, and drug release studies. In vitro release was optimized by a {3, 3} simplex lattice mixture design to achieve predetermined target release. The in vivo performance of the optimized formulation was evaluated in streptozotocin-induced diabetic rats. The results showed that floating microspheres could be successfully prepared with good yields (69–75%), high entrapment (78-97%), narrow size distribution, and desired target release with the help of statistical design of experiments from very small number of formulations. In vivo evaluation in albino rats suggested that floating microspheres of rosiglitazone could be a promising approach for better glycemic control