ACTIVITIES OF PEFLOXACIN AND CIPROFLOXACIN AGAINST MYCOBACTERIUM-LEPRAE IN THE MOUSE

  • 1 March 1987
    • journal article
    • research article
    • Vol. 55  (1) , 70-77
Abstract
Because ciprofloxacin and pefloxacin are fluoroquinolones active against many mycobacterial species, both drugs were tested against Mycobacterium leprae in the mouse foot-pad system. Preliminary pharmacokinetic studies in the mouse showed that after a single oral dose of 150 mg/kg ciprofloxacin the peak serum concentration was 3.6 .mu.g/ml, and after 50 mg/kg or 150 mg/kg pefloxacin peak serum concentrations were, respectively, 9.2 .mu.g/ml and 16.9 .mu.g/ml, the half-lives for serum elimination being about 2 hr for both drugs. The activity of daily 50 mg/kg and 150 mg/kg ciprofloxacin and pefloxacin against M. leprae was then tested in mice infected with 5 .times. 103 M. leprae. The growth of M. leprae was not prevented in mice treated continuously with either 50 mg/kg or 150 mg/kg ciprofloxacin, indicating that this drug had no or a limited bacteriostatic effect at the dosages used. In mice treated continuously with 50 mg/kg pefloxacin, growth of M. leprae was not prevented, but at monthly harvests the number of bacilli in the foot pads remained less than those of control mice (p < 0.05). No growth of M. leprae occurred in mice treated continuously with 150 mg/kg pefloxacin. In mice treated for only 3 months with daily 150 mg/kg pefloxacin, the growth-delay that followed the stopping of the drug was 126 days, suggesting that approximately 99% of the M. laprae were killed. The pharmacokinetics of pefloxacin being more favorable in man than in the mouse, pefloxacin appears a possible drug for the chemotherapy of leprosy.