Pharmacokinetics of cationic liposome-encapsulated doxycycline in mice challenged with genital infection by Chlamydia trachomatis

Our previous studies demonstrated the efficacy of cationic liposome-encapsulated doxycycline (CaL-DOX) on the course of infection with Chlamydia trachomatis in vitro and in vivo. In this investigation, the pharmacokinetics of CaL-DOX are reported. Female mice inoculated intravaginally with 4.84 x 10(5) inclusion-forming units were treated intramuscularly, 3 days postinfection, as determined by a preliminary study, with 0.1 ml of unencapsulated doxycycline (DOX) or CaL-DOX, at 10 mug/ml body weight for 3 consecutive days. Sampling was performed at 12, 24, 48, 72 and 96 h after treatment. The microbiological test was used to measure the DOX concentration in sera, liver, kidneys and genital organs. The maximum concentration in kidneys, liver and genital organs was higher in mice treated with DOX than in those treated with CaL-DOX. However, in sera, the amount was similar to that in mice treated with DOX. The DOX concentration found in mice treated with CaL-DOX was much less than in those treated with unencapsulated DOX. This may have a direct impact on the secondary effects caused by the medication. Decreased secondary effects should have a positive outcome on patient physical and mental health. Even if this study is the only one of its kind so far, CaL-DOX could be an alternative solution for the treatment of chlamydial infections. Copyright (C) 2004 S. Karger AG, Basel.