[Effects of rifamdin on pharmacokinetics of dexamethasone]

The rabbits of same sex and approximate weight, were randomly divided into following two groups: a group given all rifamdin for 12 days before dexamethasone injection and a control group without RFD. After a single IV injection of dexamethasone sodium phosphate, the concentrations of dexamethasone in rabbit plasma taken at 5, 15, 30 min, and 1, 2, 4, 8 h were analysed by reversed phase HPLC-UV. Linear regression analysis was made by LnC(t)-t. The pharmacokinetic parameters of dexamethasone in rabbits were calculated by methods of residuals. The results of main parameters, i.e. K10, beta, T1/2 beta, cls and AUD0-infinity kg-1 showed that rifamdin apparently promotes metabolic clearance of dexamethasone in plasma.