Diltiazem hydrochloride is an antihypertensive agent which undergoes extensive first pass metabolism making it a possible candidate for buccal delivery. Diltiazem mucoadhesive buccal patches were prepared using HPMC, chitosan, PVP, PVA and carbopol. The physicochemical interactions between diltiazem and the polymers were investigated by FTIR and DSC, results revealed no interaction between drug and polymers. The patches were evaluated for various physicochemical parameters, in vitro release studies and ex vivo permeation through porcine buccal mucosa. Residual solvent content in patches was determined by gas chromatography and are largely below the tolerated limits. The formulations showed an extended release of the drug upto a period of 12 hours during ex vivo permeation and showed non Fickian drug release. Stability of the optimized formulation was investigated as per ICH guidelines and was found to be stable with respect to drug content and ex vivo permeation.
Keywords: diltiazem hydrochloride buccal patches residual solvents mucoadhesion in vitro drug release ex vivo permeation.