OBJECTIVETo investigate the metabolism-based interaction between ipriflavone(IP) and other drugs in vitro.

METHODSIP and propafenone or estradiol, or other drugs were co-incubated with rat liver microsome induced by beta-naphthoflavone. The concentrations of residual substrate in microsomal incubates were determined by HPLC.

RESULTThe metabolism of propafenone (10 microg/ml) incubated with 2 microg/ml or 50 microg/ml IP was markedly inhibited compared with control group(P<0.01). While the metabolism of 10 microg/ml of estradiol incubated with 10 microg/ml and 100 microg/ml IP showed no marked inhibition. When IP (20 microg/ml) was incubated with 0.5 microg/ml propranolol, 0.5 microg/ml propafenone or 5.0 microg/ml estradiol respectively the metabolic activity of IP was markedly inhibited compared with control group (P<0.05 P<0.05 P<0.02 respectively).

CONCLUSIONThe results indicate that there is an interaction between ipriflavone and propafenone during in vitro metabolism, and there might also be clinical significance.