Simultaneous determination of mycophenolic acid and its acyl and phenol glucuronide metabolites in human serum by capillary zone electrophoresis

A simple capillary electrophoretic method was developed for simultaneous determination of mycophenolic acid (MPA) and its metabolites, acyl glucuronide (AcMPAG) and phenol glucuronide (MPAG), in human serum. The method utilized only running buffer in the separation, prior acidification of serum, and extraction with ethyl acetate. Separation was performed by capillary zone electrophoresis using 20 mM sodium acetate-acetic acid (pH 4.9) as running buffer, applied voltage of 15 kV, and UV detection at 217 nm. Each electrophoretic run was completed within 14 min. The optimized method demonstrated good performance concerning specificity, linearity (r > 0.998), sensitivity (limit of detection: for MPA, 0.10 μg/ml; for AcMPAG, 0.10 μg/ml; MPAG, 0.42 μg/ml), accuracy (87-108%) and precision (<9.3%). This method was successfully applied to measurements of MPA, AcMPAG, and MPAG in renal transplant patient samples and could be a useful alternative to HPLC-based methods.