Lack of effect of Chinese medicines on bioavailability of ofloxacin in healthy volunteers

Recently, Chinese medicines have become available as OTC drugs and are frequently prescribed with Western medicine for the treatment of various chronic diseases. In this study, the effect of the Chinese medicines Sho-saiko-to (TJ-9), Rikkunshi-to (TJ-43) and Sairei-to (TJ-114) on the bioavailability of ofloxacin (OFLX) was investigated in seven volunteers in an open, random crossover fashion. Subjects received a single oral dose of OFLX (200 mg) alone and with coadministrations of each Chinese medicine, at one-week intervals. Plasma and urine samples were analyzed by high-performance liquid chromatography. No significant differences in any estimated bioavailability parameters of OFLX were observed between the two phases. The urinary recovery of OFLX excreted within 24 h after the administration of OFLX alone, 80.6 ± 3.9% (mean ± SEM), was not significantly different from those after the coadministrations of the Chinese medicines (79.7 ± 5.1% for TJ-9, 76.8 ± 2.3% for TJ-43 and 80.3 ± 5.3% for TJ-114), suggesting that there was no difference in the systemic availability of the four doses. These findings indicate that the Chinese medicines studied have no significant effect on the rate and extent of bioavailability of OFLX.