Abstract: Aim To compare the pharmacokinetics of tacrine (THA)between young rats and aged rats.Methods After ig and iv THA 8 mg/kg,the plasma THA concentrations in rats were determined by reversed phase HPLC.The compartment model and the pharmacokinetic parameters were calculated by CAPP software.Results The concentration-time curve was de-scribed by a two-compartment open model.The concentrations of THA in aged rats were much higher than those in normal rats.After iv administration, the main pharmacokinetic paramaters in young rats such as T_1/2α,T_1/2β and AUC were 10±6 min, 60±6 min, and 34±13g/ min·L, while those in aged rats were 18±3 min, 98±19 min, and 55±7 g/ min·L, re-spectively.After ig THA,the values of T_1/2α,T_1/2β,AUC, Gm and T_p in young rats were 7±2min,63±8 min,12±5 g/ min·L, 130±58 μg/L, and 19±2 min,while those in aged rats were 9±1 min, 98±28 min, 24±10 g/min·L,218±72 μg/L,23+2 min, respectively.The parameters were significant differences between the two kinds of rats (P<0.05 or P<0.01).Conclusion The absorption, distribution and elimination of THA in aged rats were slower than those in young rats.

Key words: tacrine, young rat, aged rat, pharmacokinetics, HPLC