Rapid quantification of mirtazapine and desmethyl mirtazapine in human plasma by LC–ESI-MS/MS: Application to a bioequivalence study

High-throughout bioanalytical method based on a solid-phase extraction (spe), and rapid liquid chromatography–tandem mass spectrometry (lc–ms/ms) analysis has been developed and validated for the quantification of mirtazapine (mrt) and desmethyl mirtazapine (dmrt) in heparinized human plasma. plasma samples, without a drying and reconstitution step, were extracted by a simple spe. the analytes and imipramine (internal standard, is) chromatographed on a betasil-c18 column. the total chromatographic run time was 1.8 min per sample. response was a linear function of concentration in the range 0.1–100.0 ng/ml, with correlation coefficient p0.9994. the assay has excellent characteristics and has been successfully applied tobioequivalence study samples for estimation of mrt and dmrt in healthy human subjects.