Development and characterization of sustain release gastro retentive floating microsphere of diltiazem hydrochloride for the treatment of hypertension

Abstract

Gastroretentive drug delivery systems are the systems, which are retained in the stomach for a longer period and thereby improve the bioâ€availability of drugs. Diltiazem hydrochloride (DTZ HCl), is a calcium channel blocker, an antihypertension and antianginal drug, DTZ HCl undergoes an extensive biotransformation, mainly through cytochrome Pâ€450 CYP3A, which results in <4% of its oral dose being excreted unchanged in urine. Suffers from poor bioâ€availability (~30–40%) owing to an important first pass metabolism. It has an elimination halfâ€life of 3.5 h and an absorption zone from the upper intestinal tract. Thus, the present work is aimed to formulate sustain release floating microsphere of DTZ HCl for gastroretentive drug delivery system. Floating microsphere were prepared using nonaqueous solvent evaporation
method using polycarbonate, chitosan, ethyl cellulose, hydroxypropyl methycellulose and acrycoat as materials in various
quantities, in varying ratio to formulate 20 formulations of the floating microsphere. Observations of all formulations for physical characterization had shown that, all of them comply with the specification of official pharmacopoeias and/or standard reference. It was observed that microsphere of batch F3 followed the results obtained, it was concluded that the formulation 98.72% F3 is the best formulations as the extent of drug release was found to be around 99.81% at the desired time 12 h.

Key words: Diltiazem hydrochloride, floating microsphere, in vitro buoyancy studies, swelling index