Validation and application of a liquid chromatography-electrospray ionization mass spectrometric method for determination of mazindol in human plasma and urine.

Abstract Introduction Even after removal of some stimulants, like fenproporex, amfepramone and mazindol, from Brazilian market, the use of these substances is still high, especially by drivers. Mazindol is the second most used anorectic agent in the world acting as an indirect sympathomimetic agonist, having stimulatory action on central nervous system. Plasma is a good matrix to monitor since it reflects the psychomotor effects of these drugs, but unlike urine has an invasive collection; drug levels and detection time are quite low. Method The method involved a liquid–liquid extraction of the samples and a LC–MS analysis was fully validated. Method was used to analyze samples of urine and plasma collected from health volunteers in a period of 24 h. Metabolite of mazindol was synthesized using alkaline conditions. Results After validation the method proved to be adequate to analyze samples collected from health volunteers. Method was linear in the concentration range of 0.1–10 ng/mL (r = 0.9982) for plasma and 5–50 ng/mL (r = 0.9973) for urine. Discussion Analysis of the samples showed that mazindol can be detected after 1 h of administration and that concentration levels in urine were always higher than in plasma. Mazindol metabolite was detected only in urine.