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.