ABSTRACT:
The objective of the present study was to develop extended release matrix tablets of metoprolol succinate (25mg and 50mg label claim), to increase bioavailability; deliver the drug at a near constant rate for approximately 20 hrs independent of food intake and gastrointestinal pH. The dry granulation technique was used to compress the tablet and HPMC –K-100, Hydroxy propyl cellulose, Ethyl cellulose were used as matrixing agent. The tablets were evaluated for thickness, hardness, weight variation, friability, in vitro swelling characteristics of the matrix polymer and dissolution studies; also the drug release from the prepared tablet was compared with the marketed tablet. The drug release from batch FA10 (25mg label claim) and FB4 (50mg label claim) found to be 15.38%, 30.82%, 54.41%, 86.59% and 16.66%, 34.11%, 57.79%, 87.30% respectively in the 1st, 4th, 8th and 20th hour, comparable with the marketed extended release matrix tablet indicating that it is well suited to provide controlled and predictable release of metoprolol for nearly 20 hrs. Drug release was found to be nearly zero to zero order, governed by diffusion through swollen matrix and erosion of the matrix, showing non fickian transport. Stability studies under accelerated condition showed satisfactory results.