High-performance liquid chromatographic analysis of verapamil and its application to determination in tablet dosage forms and to drug dissolution studies

A high-performance liquid chromatographic procedure with two detectors is p resented for the determination of verapamil in pharmaceutical dosage forms. The procedure is based on the use of reversed-phase high-performance liqui d chromatography with UV and fluorimetric detectors. Each analysis required no longer than 6 min for both detection procedures. Quantification was ach ieved by measurement of the ratio of the peak area of the drug to the inter nal standard (fluoxetine) and the detection limit was 10 ng/ml for the UV d etector and 750 pg/ml for the fluorimetric detector. There was no significa nt difference between inter- and intra-day studies for verapamil determined for two different concentrations (0.05 and 1.00 mu g/ml). This process cou ld be used to determine verapamil concentrations in the range 0.025-50 and 0.0008-20 mu g/ml for UV and fluorimetric detection, respectively. These me thods were applied, without any interference from the excipients, for the d etermination of the drug in tablets and in drug dissolution studies. It is suggested that the proposed HPLC procedures could be used for routine quali ty control and dosage form assay of verapamil hydrochloride. (C) 2000 Elsev ier Science S.A. All rights reserved.