Determination of mildronate in human plasma and urine by liquid chromatography–tandem mass spectrometry

A sensitive and selective analytical method based on liquid chromatography–triple–quadrupole mass spectrometer has been developed to determine mildronate in human plasma and urine. The aim of this work was to find a valid method to study the pharmacokinetic profiles of mildronate in humans. Mildronate is a heart protection medicine, a carnitine's structural analogue, so levocarnitine was used as an internal standard for quantification. Under the electrospray ionization source positive ion mode, calibration curves with good linearities (r = 0.9998 for plasma sample and r = 0.9999 for urine sample) were obtained in the range of 1.0–20,000 ng ml−1 for mildronate. The detection limit was 1 ng ml−1. Recoveries were around 90% for the extraction from human plasma, and good precision and accuracy were achieved. This method is feasible for the evaluation of pharmacokinetic profiles of mildronate in humans, and to the best of our knowledge, this is the first report on LC–MS–MS analysis of mildronate in plasma and urine.