Bioequivalence study of two mirtazapine oral tablet formulations in healthy Chinese male volunteers

Abstract

Mirtazapine is a tetracyclic antidepressant which works relating to noradrenergic and elective serotoninergic receptors. The aim of this study was to assess the pharmacokinetic properties and bioequivalence of a newly developed tablet formulation of mirtazapine with those of an established branded formulation in healthy Chinese male volunteers. A randomized, open-label, single-dose, 2-way crossover study was conducted in healthy Chinese volunteers under fasting conditions with a washout of 14 days between the study periods. A sensitive and credible high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) method was developed and validated to determine mirtazapine in human plasma. The main PK parameters of the mirtazapine test and reference tables were as follows: mean (SD) C(max), 58.715 (23.89) and 58.255 (22.34) ng/ml; AUC(0-t), 591.406 (186.79) and 596.339 (201.25) ng × h/ml; AUC(0-∞), 627.03 (201.39) and 631.521 (227.32) ng × h/ml; t(1/2), 18.941 (4.79) and 18.285 (3.91) h; t(max) 1.417 (0.61) and 1.424 (0.75) h. The 90% CI for logtransformed ratios of C(max) (88.8 - 112.4%), AUC(0-t) (93.9 - 104.9%) and AUC(0-∞) (94.5 - 105.3%) for the test and reference formulations respectively, meeting the predetermined criteria for bioequivalence. Both treatments exhibited similar tolerability and safety. The test product is therefore bioequivalent to the reference product with respect to the rate and extent of mirtazapine pharmacokinetics.