Determination of the immunosuppressant mycophenolic acid in human serum by solid-phase microextraction coupled to liquid chromatography

A solid phase microextraction (SPME)–HPLC–UV method for the determination of the immunosuppressant mycophenolic acid (MPA) in human serum samples was developed for the first time. The procedure, that employed a carbowax/templated resin (Carbowax/TPR-100) as fiber coating, required a very simple sample pretreatment, an isocratic elution, and provides an highly selective extraction. The linear range was 0.2–100 μg ml−1. Recovery was practically unchanged (63±4%) passing from 0.2 to 100 μg ml−1 level. Within-day and between-days coefficient of variation ranged from 5.9 to 6.5% and from 8.8 to 9.2%, respectively. A detection limit of 0.05 μg ml−1 was estimated in spiked serum. The method was successfully applied to the determination of MPA in serum of a patient under mycophenolate mophetil ester (MMF) therapy, as demonstrated by the relevant concentration-time profiles.