Original Articles: 2012 Vol: 4 Issue: 9
Controlled release tablet formulations of carvedilol
Abstract
The present investigation was undertaken with an objective of formulating controlled release (CR) oral matrix tablet formulations of Carvedilol (CAR), an antihypertensive using cellulose ether polymer, Hydroxy Propyl Methyl Cellulose (HPMC K4M, HPMC K15M) of different viscosity grades as drug release retardants. The tablets were prepared by direct compression technique and evaluated for various physico-chemical/mechanical parameters. Based on the viscosity and gel formation during dissolution, HPMC K4M was selected as release retardant. The effect of different fillers like Avicel PH 101, Avicel PH 105 and Avicel PH 200 (microcrystalline cellulose), pre gelatinized starch (PGS), maize starch with spray dried lactose (FLOWLAC) on CAR release was studied and percent release of CAR at the end of 24h is in the order of FLOWLAC > Avicel PH 101 > Avicel PH 105 > Avicel PH 200 > PGS. Based on the dissolution data obtained with different fillers and keeping in view of the results from the pre-compression studies, and gel layer retaining with the matrix tablets, Avicel PH 105 was selected to carry out further formulation development. The formulation containing 25%w/w HPMC K4M as release retardant and Avicel PH 105 gave 96.59 ± 3.1% release at the end of 24h and fulfils regulatory requirement. The dissolution data was also evaluated for drug release kinetics and mechanism.