Stereoselective determination of R,S-2-[4-(3-methyl-2-thienyl)phenyl]propionic acid and its taurine conjugates in dog urine by high-performance liquid chromatography

Abstract

Two high-performance liquid chromatographic methods for the stereoselective determination of R,S-2-[4-(3-methyl-2-thienyl)-phenyl]propionic acid ( R,S-MTPPA), a new anti-inflammatory agent, and its taurine conjugates ( R,S-MTPPA-TAU) in dog urine have been developed and validated. The urine samples were subjected to solid extraction or TLC preparation, then R,S-MTPPA and R,S-MTPPA-TAU were separated on Chiralcel OD and Chiral AGP columns, respectively, with ultraviolet absorbance detection at 272 nm. The dose–response relationships for enantiomers of R,S-MTPPA and R,S-MTPPA-TAU were linear in the concentration ranges of 0.5–50 ( r>0.9993) and 5–200 μg/ml ( r>0.9982), respectively. Recoveries of all tested enantiomers from dog urine were roughly 90% within the above concentration ranges. Intra- and inter-day reproducibilities were sufficient for metabolic studies. These methods were applied to stereoselective determination of the enantiomers in dog urine after administration of either S- or R-MTPPA.