Quantitative HPLC analysis of 4-[4-4(chlorophenyl)phenyl]-4-oxo-2S(phenylthiomethyl) butanoic acid (BAY 12-9566), a metalloproteinase inhibitor, and its metabolites in human plasma

A High Performance Liquid Chromatographic (HPLC) method was developed for t he analysis of Bay 12-9566 (4-[4-4(chlorophenyl)Phenyl]-4-oxo-2S-(phenylthi omethyl) butanoic acid), a metalloproteinase inhibitor, and its three metab olites, M1 (sulfoxide), M2 (rho-hydroxy) and M3 (reduction product) in plas ma. Sample preparation involved precipitation of plasma proteins using acid ified acetonitrile. A reverse phase chromatography with gradient elution, u ltraviolet detection at 290 nm and internal standard were used for separati on and quantitation of all analytes. The quantitation range was 0.10 mu g/m L to 50 mu g/mL for BAY 12-9566, and 0.10 mu g/mL to 3.00 mu g/mL for all t hree metabolites. The limit of detection for BAY 12-9566 and for all three metabolites was 0.05 mu g/mL. Intra-day accuracy for BAY 12-9566 and the th ree metabolites ranged from 95.0 to 105.0% and precision (CV) ranged from 0 .0 to 4.76%. Inter-day accuracy and precision were based on quality control samples anal yzed concurrently with subject plasma samples during a 15 month period. Acc uracy ranged from 95.7 to 104.8% sand precision ranged from 1.46 to 7.31%.