DETERMINATION OF ASPIRIN AND SALICYLIC ACID IN PLASMA BY GC-MS AND PHARMACOKINETIC STUDIES

AIM: To develop a GC-MS method for the study of pharmacokinetics of aspirin and salicylic acid in healthy human volunteers. METHODS: A 25 m×0.2 mm ID capillary column was used. The carrier gas was helium. Benzene carbonic acid was used as internal standard. The plasma was extracted with ether—dichloromethane (4∶1) after adding 3 mol.L-1 HCl and then reacted with bis-(trimethylsilyl) trifluoroacetamide (BSTFA). The concentrations of aspirin and salicylic acid were measured by GC-MS (SIM). The pharmacokinetic parameters were computed using 3P87 program. RESULTS: A good linearity was obtained from 2.0～400 ng.mL^-1 of aspirin and 0.2～10.0 μg.mL^-1 of salicylic acid in human plasma. The detection limit of aspirin and salicylic acid were 1.0 ng.mL^-1 and 0.1 μg.mL^-1 in plasma, respectively. The results showed that the plasma concentration-time courses conformed to one compartment model following a single oral dose of 50 mg aspirin tablets given to each of the 8 volunteers. CONCLUSION: The established GC-MS method was a good method for determination of aspirin and salicylic acid in human plasma. The method was simple, precise and sensitive.