Abstract

Three different dutasteride extraction methods were compared and a method based on liquid-liquid extraction (LLE)using methyl tert-butyl ether and methylene chloride was proved to be more effective than others for the extraction of dutasterideand finasteride, the internal standard (IS), from rat plasma. Additionally, a method composed of the LLE extraction, liquid chromatography,and multiple reaction monitoring (MRM) to target dutasteride and IS was validated by assessing specificity, linearity(r2 = 0.9993, 5 - 400 ng/mL), sensitivity (the limit of detection: 4.03 ng/mL; the limit of quantitation: 12.10 ng/mL), accuracy(intra-day: 89.4 - 105.9%; inter-day: 84.9 - 100.9%), precision (intra-day: 0.8 - 6.9%; inter-day: 2.9 - 15.9%), and recovery (84.7- 107.8%). Since the validated method was successfully applied to a pharmacokinetic study of dutasteride, it can be useful for thepharmacokinetic evaluation of newly developed dutasteride formulations.