Development and validation of a highly sensitive UPLC-MS/MS method for the determination of Huperzine A in rat plasma.

Huperzine A is a reversible and selective cholinesterase inhibitor and has been approved for the treatment of Alzheimer's diseases. In this study, we developed a highly sensitive and specific ulta-high-performance liquid chromatography-tandem mass spectrometry method for the determination of Huperzine A in rat plasma. An aliquot of 50 μL of rat plasma sample was pretreated with 200 μL of acetonitrile-methanol (v/v; 1:1) containing 0.2% formic acid followed by solid phase extraction. The resulting sample was separated on a Waters ACQUITY BEH C18 column using acetonitrile and water containing 0.2% formic acid as mobile phase, at a flow rate of 0.3 mL/min. Multiple-reaction monitoring (MRM) mode was used for quantitative analysis of Huperzine A in positive electrospray ionization. In the concentration range of 0.01-10 ng/mL, Huperzine A showed excellent linearity with correlation coefficient > 0.998. The intra- and inter-day RSD% were less than 9.7%, while the RE% ranged from -6.7% to 10.0%. The mean recovery was >84.5%. The validated method was demonstrated to be selective, sensitive, and reliable, which has been successfully applied to pharmacokinetic study of Huperzine A in rat plasma. Huperzine A displayed a long half-life in rat plasma and high oral bioavailability.