Controlled drug delivery of diltiazem hydrochloride as transdermal patches: a novel approach on formulation evaluation in vitro and in vivo parameters

A significant effort was done to formulate transdermal patches (Paranjothi 1998) of Diltiazem Hydrochloride (DH), a benzothiazepine calcium channel blocker, mainly meant for the treatment of hypertension, chronic stable angina pectoris; by using hydroxy ethyl cellulose, ethyl cellulose and Eudragit RLPO. Six batches of transdermal patches were prepared by solvent casting technique in which the best formulation was found out. The polymers HEC, EC and Eudragit RLPO were incorporated with Diltiazem Hydrochloride in various proportions, out of which the best formulation on the ratio [HEC: EC: EUDRAGIT RLPO-1:1:2] with the drug was determined. The prepared transdermal patches were spherical, uniform in shape and white in color. The obtained transdermal films were evaluated for physico-chemical characteristics, in vitro release profile and in vivo evaluation in albino mice. Higuchis plot studies revealed that the predominant mechanism of drug release was diffusion