Duration of vaginal retention and potential duration of antiviral activity for five nonoxynol-9 containing intravaginal contraceptives

OBJECTIVE: The purpose of this study was to determine the vaginal retention of five nonoxynol-9 intravaginal contraceptives. METHOD: An open-label crossover study in 10 premenopausal volunteers was performed at an outpatient clinical research center. The outcomes are described utilizing the median and range. RESULT: At 8 h post-instillation, the median amounts of nonoxynol-9 present in the vagina were: Delfon 7.68 mg, Conceptrol 5.18 mg, Advantage 24 1.95 mg, VCF 1.74 mg, and Semicid 1.51 mg respectively. Our calculated theoretical minimal amount needed to protect against HIV infection is 2.00 mg. CONCLUSION: The best vehicle for retaining nonoxynol-9 in the vagina appears to be foam. Further research in the effectiveness of nonoxynol-9 in prevention of the spread of HIV infection should be directed toward the use of foam vehicles to deliver nonoxynol-9 to the vagina.