Chemiluminescence determination of tiopronin and its metabolite 2-mercaptopropionic acid in human urine by HPLC coupled with flow injection

In previous pharmacokinetic studies tiopronin, a drug used for effective treatment of cystinuria and rheumatoid arthritis, and its metabolite 2-mercaptopropionic acid were analysed by conventional liquid chromatography with pre- and post-column derivatization and UV detection. Now a novel HPLC-coupled chemiluminescence-flow-injection analysis (CL-FIA) method has been developed for the determination of tiopronin and 2-mercaptopropionic acid in urine. The method is based on chemiluminescence from a Ce(IV) oxidation system sensitized by quinine, as proposed earlier by this group, and flow-injection analysis. The method, which has the advantages of high sensitivity and selectivity, simple sample treatment and prompt production of results, has also been preliminarily adapted for pharmacokinetic study of tiopronin in urine.