Quantification of trimetazidine in human plasma by liquid chromatography-electrospray ionization mass spectrometry and its application to a bioequivalence study.

A rapid, sensitive and specific liquid chromatography-electrospray ionization mass spectrometric (LC-ESI-MS) method has been developed for the quantification of trimetazidine in human plasma. The analyte and the internal standard (pseudoephedrine) were extracted from plasma samples with n-hexane-dichloromethane (1:1, v/v) and analyzed on a C18 column. The chromatographic separation was achieved within 3.5 min using the mobile phase consisting of methanol/0.05% formic acid (80:20, v/v) and the flow rate was 1.0 ml/min. Ion signals m/z 181.0 and 148.0 were measured in the positive mode for trimetazidine and pseudoephedrine, respectively. The calibration curves were linear within the range of 0.4 to approximately 120 ng/ml. The lower limit of quantification (LLOQ) was 0.4 ng/ml with 0.5 ml plasma sample. The intra- and inter-day precisions were lower than 12% in terms of relative standard deviation (RSD). The inter-day relative error (RE) as determined from quality control samples (QCs), ranged from -1.4% to 3.3%. This validated method was successfully applied to the bioequivalent evaluation of two brands of trimetazidine tablets in 20 healthy volunteers.