title: Assessment of a new spermicidal agent against ejaculated dog and human spermatozoa in vitro.
abstract: The spermatostatic potencies of a new vaginal contraceptive agent, RS-37367, and a standard surfactant compound, nonoxynol-9, have been compared by using ejaculated dog and human spermatozoa. RS-37367 was 25 to 50 times more potent than nonoxynol-9 against dog spermatozoa. Nonparallel concentration-response lines were obtained against human spermatozoa. Concentrations of RS-37367 causing immediate spermatostasis against dog spermatozoa resulted in vesiculation of the plasma and outer acrosomal membranes of spermatozoa; similarly, immediately spermatostatic concentrations of nonoxynol-9 were associated with the previously documented generalized membrane stripping. The activities of both RS-37367 and nonoxynol-9 were affected by the concentration of dog spermatozoa in semen-compound mixtures. Short-term (5-minute) exposure of spermatozoa to concentrations of RS-37367 not immediately spermatostatic resulted in progressive immobilization of spermatozoa. Extensive washing of the spermatozoa was not able to reverse this effect, in contrast to spermatozoa transiently exposed to nonoxynol-9.
mesh_terms: D000818:Animals; D003271:Contraceptive Agents, Female / Q000494:pharmacology*; D004285:Dogs; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology*; D008297:Male; D017137:Nonoxynol; D011092:Polyethylene Glycols / Q000494:pharmacology*; D013081:Sperm Motility / Q000187:drug effects; D013089:Spermatocidal Agents / Q000494:pharmacology*; D013094:Spermatozoa / Q000187:drug effects
chemical_list: D003271:Contraceptive Agents, Female; D007093:Imidazoles; D013089:Spermatocidal Agents; D017137:Nonoxynol; D011092:Polyethylene Glycols; C038684:1-(2-(2,4-dichlorobenzyloxy)-n-octyl)imidazole oxalate