Design and Development of Bilayer Floating Tablets of Diltiazem Hydrochloride

Diltiazem hydrochloride is a calcium channel blocker which undergoes extensive hepatic first pass metabolism by liver; its absorption from upper part of GIT is very low and has poor oral bioavailability of 40% - 60%. In the present investigation Diltiazem Hydrochloride was formulated as a bilayer floating tablets in order to achieve the Gastric residence time and to minimize the flactuations in blood level i.e the drug was released from the SR layer. Bilayer floating tablets were prepared by wet granulation method. Immediate release layer was formulated by using various suerdisintegrantents such as sodium starch glycolate, croscarmellose sodium and crospovidone and sustained release layer was formulated by different grades hydrophilic polymers i.e. HPMCK4M, HPMCE5 and HPMCK100M.The drug- excipient compatibility studies were conducted by IR spectroscopy. The tablets were evaluated for weight variation hardness, friability, drug content, swelling index, in-vitro buoyancy studies and in-vitro dissolution studies. The drug was released from an immediate release layer was 20mins followed by sustained release layer for 12hrs.The dissolution data were fitted into zero order, first order, Higuchi and Peppas mechanism. The drug release from the formulation F20 followed first order kinetics and exhibited Peppas transport mechanism.