Determination of Huperzine A in Human Plasma by LC-MS/MS and Its Application to Relative Bioavailability of Huperzine A Tablets

OBJECTIVE To study the pharmacokinetics and bioequivalence of huperzine A in human after oral administration using a simple LC-MS/MS method. METHODS Plasma was extracted with ethyl acetate after the addition of the internal standard, codeine phosphate. The separation was achieved on a reversed- phase C18 column. Target ions were 243/210 for huperzine A and 300/199 for codeine phosphate. Twenty four healthy male volunteers received an oral dose of 0.4 mg huperzin A in a two treatment, open, crossover design. The plasma samples were collected for 15 h. Various pharmacokinetic parameters such as peak concentration(ρmax), time for peak concentration (tmax), AUC0 -t, and elimination half-life (t1/2) were calculated for both of the two formulations. RESULTS The calibration curves were in the range of 0.252-25.2 μg·L-1. The mean AUC0-t value for formulation R was found to be (1 479.165±288.738)μg·h·L-1 and that for formulation T was (1 384.079±325.094)μg·h·L-1 respectively. ρmax were (3.558±0.973) and (3.062±0.821)μg·L-1. tmax were (44.17±20.62) and (47.92±12.85)min. CONCLUSION The relative bioavailability is (94.4±18.7)% for AUC and (86.3±15.4)% for ρmax. Formulation T is bioequivalent with Formulation R.