In vitro spermicidal activity of parabens against human spermatozoa

Potent in vitro spermicidal activity of parabens against human spermatozoa was demonstrated in this study. The "pass" point concentration of the four parabens--methylparaben, ethylparaben, propylparaben, and butylparaben, at which all spermatozoa were immobilized and no immobilized spermatozoon revived after 30 min incubation in phosphate buffered glucose solution, was 6, 8, 3, and 1 mg/ml, respectively, as tested by Harris' method. These parabens are used as food and pharmaceutic preservatives; less toxicity and side effects were expected for the development of parabens as vaginal contraceptive agents.