Determination of a novel anti-influenza pinanamine-based analog in rat plasma by liquid chromatography-tandem mass spectrometry and its application in pharmacokinetic evaluations

A pinanamine-based analog, (1R,2R,3R,5S)-N-((3-cyclopropylthiophen-2-yl)methyl)-2,6,6-trimethylbicyclo[3.1.1]heptan-3-amine (M090) was synthesized and demonstrated with anti-influenza activity to overcome the multi-drug resistance. Herein, a rapid and robust liquid chromatography-tandem mass spectrometry method was developed and validated to quantify M090 in rat plasma. With simple protein precipitation by methanol, the separation of M090 was performed on a Waters BEH-C18 column (2.1 x 100 mm, 1.7 mu m) by gradient elution at 0.4 mL/min with mobile phases consisting of water containing 0.1 % formic acid (phase A) and methanol (phase B). M090 and clenbuterol (internal standard) were detected using multiple reaction monitoring in positive electrospray ionization mode with transitions of m/z 290.3 -> 137.0 and m/z 277.0 -> 203.0, respectively. The method was validated over a linear range of 1.0-2400 ng/mL with a regression coefficient of 0.9974 and no endogenous interference. The intra- and inter-batch precisions were within 8.29% and accuracy ranged from 100.3% to 108.1% for M090. The validated method was utilized to evaluate the in vitro metabolic stability and in vivo pharmacokinetics of M090 in rats.