Determination of mirtazapine in spiked human plasma and tablets by first derivative spectrofluorimetric method.

A sensitive first derivative spectrofluorimetric method ((1)D-spectrofluorimetry) was developed for the determination of mirtazapine. Calibration graph for mirtazapine determination was established using the first derivative amplitudes of the mirtazapine emission spectrum (λ ex = 314 nm) in 0.1 M sulphuric acid measured at 375-435 nm from peak to peak, as the analytical signals. Moreover, the ratio of (1)D-spectrophotometric peak amplitudes at these wavelengths was calculated and used for the detection of the presence of interferences. Linearity range was found to be between 1 and 40 ng ml(-1) with correlation coefficient (r) = 0.9999. The limit of quantitation (LOQ) was 1.0 ng ml(-1) and the limit of detection (LOD) was 0.2 ng ml(-1). The proposed method was validated according to ICH; and it has been applied for the drug determination in human plasma without prior extraction and in tablets. The proposed method's accuracy, reproducibility, selectivity and simplicity suggest its application in quality control analysis of the drug.