4-bromo-7-hydroxyindan oxime--a new potent spermicidal agent.

The spermicidal effect of eleven chelating agents with a ring structure was evaluated using human spermatozoa. All were potent spermicides in vitro. 4-Bromo-7-hydroxyindan oxime (S-11) was the most potent and its lowest effective concentration for immobilizing sperm within 20 sec was 0.02 mg/ml; its toxicity was also the lowest of the compounds tested with an acute LD50 of 2936 mg/kg. In rabbits, S-11 caused no local irritation to the conjunctiva or quadriceps femoris muscle at a concentration of 0.02 mg/ml. Heart, liver, kidney, spleen, lung and vagina showed no pathological changes when vaginal pessaries containing 1 or 10 mg of S-11 were administered daily, six times a week for 90 days. When vaginal pessaries of 8 or 40 mg S-11 were administered on days 7-15 after mating, no significant abnormality in general appearance, in the viscera or bone development of foetuses were found.