Determination of oxidized and reduced glutathione in pharmaceuticals by reversed-phase high-performance liquid chromatography with dual electrochemical detection

A sensitive and rapid reversed-phase HPLC method with electrochemical detec tion was developed for the analysis of glutathione in pharmaceutical prepar ations. The separation was achieved on an LC 18-DB (100x4.6 mm I.D.; 5 mu m particle size) column. The mobile phase consisted of 0.1% (v/v) trifluoroa cetic acid and acetonitrile (98:2, v/v). The effluent was monitored with du al electrochemical detection (applied potentials: E-1 = +0.450 V; E-2 = +0. 750 V) in order to check simultaneously the declared amount of reduced glut athione and to quantify the related impurity oxidized glutathione. Limits o f detection of 0.60 and 0.15 ng were achieved for the reduced and oxidized form, respectively. The method was validated and applied to the analysis of five commercial preparations containing reduced glutathione. (C) 1999 Else vier Science B.V. All rights reserved.