title: Simplified reversed-phase HPLC method with spectrophotometric detection for the assay of verapamil in rat plasma.
abstract: A high-performance liquid chromatographic (HPLC) method was developed for the assay of verapamil in rat plasma. After deproteinization of the plasma sample with an acetonitrile-perchloric acid (8:2) mixture containing dextromethorphan, the internal standard, an aliquot of the supernatant was directly analyzed on a cyanopropylsilane column with methanol-acetonitrile-triethylamine acetate buffer (10:30:60) as the mobile phase and detection at 235 mm. At a flow rate of 1.5 ml min-1, a complete analysis was completed in less than 6 min. The method was linear for verapamil concentrations in the range 0.5-10 micrograms ml-1 (r = 0.9999). Recoveries for the same drug concentrations from spiked rat plasma ranged from 85.6-93.0% (n = 8). The mean RSD values for intraday and interday assay reproducibility (n = 3) were, in both cases, less than 0.9%. The limit of detectability was about 0.1 microgram ml-1. The method was found useful to monitor the plasma levels of verapamil in rats that had received this drug by the nasal, oral and intravenous routes of administration.
authors.affiliation: St John's University, College of Pharmacy and Allied Health Professions, Jamaica, New York 11439, USA.
authors.forename: C A
authors.initials: CA
authors.lastname: Lau-Cam
authors.forename: D
authors.initials: D
authors.lastname: Piemontese
mesh_terms: D000818:Animals; D001798:Blood Proteins / Q000737:chemistry / Q000302:isolation & purification; D002121:Calcium Channel Blockers / Q000097:blood* / Q000493:pharmacokinetics; D002851:Chromatography, High Pressure Liquid; D010949:Plasma / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D013056:Spectrophotometry, Ultraviolet; D014700:Verapamil / Q000097:blood* / Q000493:pharmacokinetics
chemical_list: D001798:Blood Proteins; D002121:Calcium Channel Blockers; D014700:Verapamil