Quantitation and Stability of Verapamil Hydrochloride using High-Performance Liquid Chromatography

Abstract

A high-performance liquid chromatography method for the quantitation of verapamil hydrochloride in pharmaceutical dosage forms has been developed. The method is precise and accurate with a relative standard deviation of 0.63% based on six injections. No preliminary extraction procedure is required to assay injections and a very simple extraction procedure is needed for tablets. There is no interference from the excipients and the method appears to be stability-indicating. The optimum pH range of stability is about 3.2 to 5.6 and the phosphate buffer and ionic strength have very little effect on the stability. Verapamil hydrochloride appears to be a very stable compound since in 105 days at 50°, the aqueous solutions (0.5 mg/ml) did not decompose.