ASSESSMENT OF NEW FORMULATIONS OF NONOXYNOL-9 COPRECIPITATED WITH POLYVINYLPYRROLIDONE AND IODINE AS POSSIBLE VAGINAL CONTRACEPTIVES

Objective: To assess the in vitro spermicidal activity of new formulat ions of nonoxynol-9, coprecipitated with polyvinylpyrrolidone (PVP) or iodinated PVP, against human spermatozoa via the use of the Sander-Cr amer test and the cervical mucus penetration test. Design: Solutions o f PVP-nonoxynol-9 and iodinated PVP-nonoxynol-9 containing nonoxynol-9 whole molecule (oligomers 1 to 18) and its isolated fractions (oligom ers 8 to 10, 4 to 6, and 1 to 3) at various concentrations (mu g/mL) w ere prepared via serial dilutions. Spermicidal solutions were mixed wi th human semen to determine the minimal lethal dose (mu g/mL). In the Sander-Cramer test, the lethal dose was reported as the minimal dose c apable of killing spermatozoa within 20 seconds. In the cervical mucus penetration test, the lethal dose was reported as the minimal dose ca pable of preventing penetration of spermatozoa into cervical mucus bey ond the second millimeter length of the capillary. Setting: Andrology laboratory, University of Kentucky, Lexington, Kentucky. Patient(s): N ormospermic male donors. Main Outcome Measure(s): Spermicidal lethal d ose determination of various nonoxynol-9 preparations containing the w hole nonoxynol-9 molecule and its isolated fractions coprecipitated wi th PVP or iodinated PVP. Result(s): The use of PVP increased the aqueo us solubility of the nonoxynol-9 formulations containing oligomers 1 t o 18 and 8 to 10 slightly. The coprecipitation of the nonoxynol-9 form ulations containing nonoxynol-9 oligomers 4 to 6 and 1 to 3 with PVP s ignificantly increased their solubilization and spermicidal action in vitro. Moreover, the incorporation of iodine significantly decreased t he minimal nonoxynol-9 dose required for complete killing of spermatoz oa in preparations containing nonoxynol-9 oligomers 4 to 6 and 1 to 3. Conclusion(s): Incorporation of all three components tested in this s tudy (PVP, nonoxynol-9, and iodine) enhanced the efficiency of the spe rmicidal preparations, especially for nonoxynol-9 preparations contain ing nonoxynol-9 oligomers 4 to 6 and 1 to 3.