Simultaneous Determination of Lidocaine (Lignocaine) and Thiopental in Plasma Using High Pressure-Liquid Chromatography

Abstract

Abstract A sensitive and precise high-pressure liquid chromatographic method for the simultaneous quantitation of lidocaine (lignocaine) and thiopental in 0.5 ml samples of plasma is described. Extraction was conducted at pH 7.0 using ethyl acetate, and bupivicaine was employed as an internal standard. The drugs were eluted from a reversed-phase column using a mobile phase consisting of aceton-itrile/0.2 M phosphate buffer pH 4.0 (1:9) at a flow rate of 1.0 ml/min. The drugs were detected and quantified by their UV absorption at 205 nm. The sensitivity limits of detection for lidocaine and thiopental were 1 ug/ml and 5 ug/ml, respectively. Atropine, caffeine and meperidine were found to have interfering retention times.