In vitro anti-trichomonad effectiveness of a gossypol-metronidazol blend

With the aid of the Basic Sequential Analytical Simplex Method the in vitro anti-trichomonad effectiveness of several metronidazole/gossypol blends was determined. While the combination that produced 50% of growth inhibition on trichomonad cultures (IC50) contained 15.1 microM gossypol and 0.087 microM metronidazole, the IC(50) of metronidazole and gossypol tested separately was 38.08 microM and 0.195 microM, respectively. Thus, the IC50 of mixed gossypol and metronidazole was, respectively 60.34 and 55.4% lower than that of each separated drug. Whereas metronidazole is usually administered orally, gossypol, used as spermicide, is formulated as pessary. In such conditions the absorption of metronidazole is very efficient while that of gossypol is strikingly poor. The above suggest that a gossypol-metronidazole anti-trichomoniasis therapeutic scheme could be as effective as metronidazole alone, but less toxic.