Comparison of antibacterial activity and pharmacokinetics of tinidazole with metronidazole in mice

    GAO Suª²Li, GU Yi, HUANG Baoª²Wen

    1Department of Pharmacy, Xijing Hospital, Fourth Military Medical University, Xi¬ðan 710033, 2Department of Pharmacy, PLA 304 Hospital, Beijing 100037, China

    ¡¾Abstract¡¿ AIM: The activities and pharmacokinetics of tinidazole and metronidazole were compared in vitro and in vivo. METHODS: The susceptibility of two clinical isolates and oneª²reference strain to tinidazole and metronidazole was determined in vitro by the agar dilution method. The efficacy of tinidazole was studied in neutropenic mice infected by Peptostreptococcus anaerobius. The plasma samples collected were analyzed by reversedª²phase highª²performance liquid chromatography on a C18 bonded silica column with UV detector at wavelength 317 nm. The parameters of pharmacokinetics were calculated with 3P87 program by computer. RESULTS: The results showed that tinidazole acted against anaerobic bacteria at a concentration of 0.125-1 mg/L. The 50% effective doses (ED50) of tinidazole and metrodazole were 9.6 and 13.2 mg/kg in the neutropenic mice infected by Peptostreptococcus anaerobius, respectively. The efficacy of tinidazole was more effective than that of metronidazole. The elimination half lives of tinidazole and metrodazole were 1.86 and 1.26 h in mice, respectively. CONCLUSION: The elimination of tinidazole is lower and the concentrations in plasma are higher compared with those of metronidazole, suggesting that tinidazole may be more effective in the therapy of anaerobic bacterial infections. ......