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

Abstract

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.