Effects of ambroxol on pharmacokinetics of rifampicin in rats

Objective: To study the effect of ambroxol on pharmacokinetics of rifampicin in rats in order to evaluate the interaction between the two drugs and the rationality of drug combination.Methods There are two dosage regimens to administrate rats separately as follows: ① the single group,with rifampicin administered at a dose of 30 mg/kg through tail vein;② the combination group,with ambroxol hydrochloride at a dose of 15 mg/kg through tail vein and rifampicin administrated at a dose of 30 mg/kg after 20 min,and the blood samples were collected into heparinized tubes at 10 min、30 min、1、2、4、6、8、10、14、20 h after adminstration.The concentration of rifampicin in rat′s plasma was tested by reverse HPLC-UV.The pharmacokinetic parameters of rifampicin of two groups were calculated by statistical software BAPP according to the time course.Results The main pharmacokinetic parameters of Ke,t1/2,AUC0→20 and AUC0→∞ for the single group were 0.09/h,7.35/h,391.65 h/(μg·mL) and 424.10 h/(μg·mL) respectively;those for the combined group were 0.09/h,7.34/h,368.59 h/(μg·mL) and 424.10 h/(μg·mL),respectively.There was no significant difference between the two groups.Conclusion There exists synergism when they are administered together.It is safe to combine them and there is no need to adjust the dosage of rifampicin in clinic treatment when co-administrated with ambroxol.