Evaluation of antifertility effect of gel formulation containing sperm immobilizing factor: In vitro and in vivo studies

Sexually active women often seek protection against unplanned pregnancies. Latter can be effectively controlled by consistent use of spermicides during each coital act. However, side effects associated with the use of available synthetic spermicidal agents have directed the interest towards identifying newer and safer agents. Present studies were undertaken to formulate a vaginal contraceptive gel, containing sperm immobilizing factor (SIF) isolated from Staphylococcus aureus using 1% w/v Carbopol. SIF loaded gel formulation was characterized for various in vitro parameters i.e. pH, spreadability, texture profiling, rheological properties, and in vitro release studies. The prepared formulation was found to possess significant spreading properties, gel firmness and strength, and released about 80% of SIF within 30min. Latter can completely immobilize human spermatozoa within 20s, at a dose of 200μg/ml. SIF in the proposed gel formulation showed 100% contraceptive effect when used at amount as low as of 10μg, thus confirming the possibility to develop it as a potent vaginal contraceptive for future use.