ABSTRACT:
Diltiazem hydrochloride, a water soluble drug, has a short half life of 3 to 4.5 hours and a limited window of absorption. This necessitates the formulation of this drug as a controlled release tablet. So the present work was aimed to extend the release of diltiazem hydrochloride from matrix tablets by sintering technique. For this purpose polymers like HPMC K4M and HPMC K15M were used. These polymers were added in different concentrations to the active ingredient and other excipients. The formulation was then punched into tablets and kept in a desiccator for 3 hours and 6 hours for sintering. The desiccator must be previously saturated with acetone vapors for 24 hours. After sintering, the tablets were removed from the desiccator, and dried at room temperature for 24 hours to evaporate the adhering acetone and were finally dried in a vacuum desiccator at 30° C over fused calcium chloride for 24 hours to remove the residual acetone from the tablets and stored in desiccator for further studies. The tablets were subjected to all the evaluation tests of tablets. The results proved that tablets sintered for 6 hours were harder and released drug at a slower rate than those sintered for 3 hours. Also HPMC K15M was found to be better rate controlling polymer than HPMC K4M. As a whole, tablets containing HPMC K15M and sintered for 6 hours released drug for longer period of time than the other tablets formulated.