Evaluation of the in vivo efficacy of a new vaginal contraceptive agent in stumptailed macaques

Abstract

The effect of precoital vaginal placement of three spermicidal formulations on postcoitally recovered vaginal and cervical spermatozoa was compared. Periovulatory stumptailed macaque monkeys were administered intravaginally 1 ml of Ramses Contraceptive Vaginal Jelly (C. Schmid Products Company, Little Fall, NJ), or a pluronic gel formulation containing 0, 0.1, or 1.0% of a new spermicidal compound, RS-37367. All spermicide-containing formulations reduced the motility of both vaginal and cervical sperm, compared with the gel containing no spermicide. The 1.0% RS-37367 formulation was particularly effective. No motile spermatozoa were recovered from either location, and only 0.5% of the numbers of cervical spermatozoa recovered in control animals were recoverable from this treatment group (P less than 0.0003). The formulation containing 0.1% RS-37367 appeared to be bioequivalent to the Ramses formulation containing 5% nonoxynol-9. These in vivo results support previous in vitro comparisons in which RS-37367 was estimated to be 50 times as potent a spermatostatic agent as nonoxynol-9.