Determination of mirtazapine in human plasma by liquid chromatography

A rapid high-performance liquid chromatographic method for the quantitation of mirtazapine in human plasma is presented. The method is based on a liquid-liquid extraction and reversed-phase chromatography with fluorimetric detection. The separation was performed on a Luna microm C(18)(2) 50 x 4.6 mm I.D. column using an isocratic elution. Zolpidem hemitartrate was used as the internal standard. The between-day precision expressed by relative standard deviation was less than 5% and inaccuracy does not exceed 6%. A low limit of quantitation (1.5 ng/ml) and a short time of analysis (4 min) makes this assay suitable for pharmacokinetic studies.