ABSTRACT
Objective: To develop an LC-MS/MS method for the determination of donepezil and rivastigmine in human serum. Methods: After protein precipitation with 600μl acetonitrile, the serum samples were analyzed by LC-MS/MS. Using loratadine as the internal standard, a Waters Xselect CSH C18(150 mm×3 mm, 2. 5 μm) column was used with the mobile phase consisting of water (containing 10 mmol·L-1ammonium acetate)-acetonitrile(20 ∶ 80)at a flow rate of 0. 4 ml·min-1with the column temperature at 40 ℃. The ion transitions were performed in a positive electrospray ionization multiple reaction-monitoring mode regarding [M+H] +as the molecular ion peak of donepezil and rivastigmine monitored with m/z 380. 1→m/z 91. 1 and m/z 251→m/z 206. 5, respectively. The internal standard was monitored with m/z 383. 1→m/z 337. 1. Results: The linear range of donepezil and rivastigmine was 0. 5-400 ng·ml-1(r>0. 99) and the lowest quantification limit was 0. 5 ng·ml-1. For donepezil, the intra-day and inter-day RSD was 2. 06% to 12. 51% , the relative error was -6. 60% to 4. 20% , and the relative recovery was ranged from 80. 76% to 96. 17% (RSD<15% ). For rivastigmine, the intra-day and inter-day RSD was 1. 69% to 9. 31% , the relative error was -5. 58% to 5. 20% , and the mean relative recovery was ranged from 96. 69% to 100. 15% (RSD<15% ). For the two compounds, the serum samples were stable at -40℃ for 75 d and kept stable after three repeated freeze-thaw cycles. The prepared samples were stable in the automatic sample injector (4℃) for 5 h (RSD<15% ). Conclusion: The developed assay method can be applied in the therapeutic monitoring and pharmacokinetic study of donepezil and rivastigmine in human serum.