Pharmacokinetics of Xiongbing Microemulsion in Rabbit with Different Routes of Administration

OBJECTIVE:To investigate pharmacokinetic characteristics of ligustrazine(tetramethylpyrazine as chemical name,TMP) in rabbit after intragastric(i.g.) and intravenous(i.v.) administration of Xiongbing microemulsion.METHODS:The plasma concentration of TMP was determined by HPLC after i.g.and i.v.administration.The data were processed by DAS 2.1 software to calculate the pharmacokinetic parameters.RESULTS:The linear range of TMP was 0.062-6.200 μg·mL-1.The pharmacokinetics of TMP was fitted to two compartment model after i.g.and i.v administration.The main pharmacokinetic parameters for TMP were as follow:t1/2α were 7.618 min vs.2.842 min,t1/2β were 56.417 min vs.20.318 min,V were 3.161 L·kg-1 vs.0.411 L·kg-1,Cl were 0.069 L·min-1·kg-1 vs.0.027 L·min-1·kg-1,AUC(0-∞) were 55 594.712 μg·min·L-1 vs.149 207.814 μg·min·L-1,MRT(0-∞) were 76.356 min vs.24.805 min.The absolute bioavailability of TMP was 37.26% after i.g.administration.CONCLUSION:TMP distribute slowly with i.g.administration and the mean residence time is long,while the absolute bioavailability is relatively low.On the contrary,TMP distributed rapidly with i.v.administration.There are rapid metabolism and short duration,which is not good for the efficacy of drugs.