Determination of a new immunosuppressant, mycophenolate mofetil, and its active metabolite, mycophenolic acid, in rat and human body fluids by high-performance liquid chromatography.

Mycophenolate mofetil, a new immunosuppressant, is a morpholinoethyl ester of mycophenolic acid. A new selective, sensitive and simple high-performance liquid chromatographic method was developed for the determination of mycophenolic acid and mycophenolate mofetil in biological samples. The preparation of samples was based on liquid-liquid extraction. The compounds were separated on a CN column using acetonitrile-0.01 M phosphate buffer (1:4, v/v) as the mobile phase. UV detection was used at wavelengths 215 and 304 nm. The detection limit was 5 ng per injection volume. This method enabled pharmacokinetic and pharmacodynamic studies in humans and rats.