BIOSYNTHESIS, CHARACTERIZATION AND DIRECT HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC ANALYSIS OF GEMFIBROZIL 1-O-BETA-ACYLGLUCURONIDE

Gemfibrozil 1-O-beta-acylglucuronide was purified from the urine of a volunteer administered gemfibrozil, and an isocratic reversed-phase HP LC method was developed for its direct measurement. Quantitation of ge mfibrozil and gemfibrozil 1-O-beta-acylglucuronide was carried out fro m plasma, following extraction from acidified specimens into ethyl ace tate, on a 5-mu m CN reversed-phase column with a mobile phase (pH 3.5 ) containing acetonitrile, tetrabutylammonium sulphate and distilled w ater, using fluorescence detection at 284 nm excitation and 316 nm emi ssion. Calibration curves were linear for both compounds over a concen tration range of 0.1 to 40 mg/l, with intra-assay coefficients of vari ation <5% at concentrations of 20.0, 2.0 and 0.2 mg/l, and inter-assay coefficients of variation <10%. No degradation of gemfibrozil 1-O-bet a-acylglucuronide was detected as a result of the analytical procedure . However, a preliminary application of the method indicates that gemf ibrozil acylglucuronide is chemically unstable undergoing intra-molecu lar rearrangement and hydrolysis under physiological conditions.