DEVELOPMENT OF GASTRO RETENTIVE FLOATING MATRIX TABLETS OF DILTIAZEM HYDROCHLORIDE

Abstract

The objective of the present investigation was to formulate and evaluate hydrodynamically balanced floating matrix controlled drug delivery system of diltiazem hydrochloride. Floating matrix tablets are associated with advantages of increased bioavailability and minimizing the dosing frequency. Diltiazem hydrochloride is a calcium channel blocker, an anti-hypertensive and anti-anginal drug, which undergoes extensive firstpass metabolism and display poor bioavailability. It has an elimination half-life of 3 to 4.5 h and an absorption zone from the upper intestinal tract. Gastric floating of diltiazem hydrochloride tablets results from effervescence produced by the reaction between sodium bicarbonate and hydrochloric acid in stomach. Seven formulations of floating tablets were prepared using direct compression technique with low viscosity polymer such as HPMC K100LV, high viscosity polymers such as HPMC K4M, K15M, and carbopol in different ratios. The evaluation results revealed that all formulations comply with the specification of official pharmacopoeias and/or standard reference with respect to general appearance, content uniformity, hardness, friability and buoyancy. Accelerated stability studies carried out at different temperatures, 27 ± 2 °C, 40 ± 2 °C and 7 ± 2 °C did show no changes in physicochemical properties at the end of 8 weeks indicating all the formulations are stable. Out of all the formulation developed, formulation F6 containing equal ratio of HPMC K4M and K100LV showed optimum floating time and in vitro drug 6 release of 82.19% at the end of 8 h. Thus it is summarized; high viscosity grade polymer HPMC K4M, low viscosity grade polymer HPMC K100LV and carbopol can be successfully used in formulation of sustained release gastro retentive floating drug delivery system.