Rapid liquid chromatographic assay for the determination of acetaminophen in plasma after propacetamol administration:: application to pharmacokinetic studies

A simple method for the rapid estimation of acetaminophen in plasma is described here, p-Propionamidophenol was used as internal standard. The assay involved a single ethyl acetate extraction and liquid chromatographic analysis at a wavelength of 242 nm using a reversed-phase encapped column, with a mobile phase of acetonitrile and 0.005 M potassium dihydrogen phosphate adjusted at pH 3.00. The limit of quantitation of acetaminophen by this method was 0.05 mu g ml(-1), only 0.1 mi of the plasma sample was required for the determination. The calibration graph was linear from 0.05 to 100 mu g ml(-1). Intra and inter-day precision (CV) did not exceed 8.93%. Mean recoveries of 90.31% with a CV of 1.38% were obtained. Applicability of the method was demonstrated by a pharmacokinetic study in normal volunteers who received 2 mg propacetamol. (C) 1999 Elsevier Science B.V. All rights reserved.