Title : Efficacy and safety of a new vaginal contraceptive formulation containing sperm immobilizing factor isolated from Staphylococcus aureus
Abstract:
The growing population is a worldwide problem today – the total earth’s population of 7 billion is expected to rise by approximately two more billions by 2050. Besides population explosion, unintended pregnancies and elective abortions are a major public health issue. Contraception is considered as the key solution to cope up with these issues. Although an array of methods is known for female contraception, which includes barrier methods, hormonal methods, IUDs, sterilization and natural methods, none of these methods can be considered as ideal. Consequently, one of the challenging pursuits in the realm of contraceptive field is the development of contraceptives that are effective, safe, reversible, cost effective and virtually imperceptible is extremely desirable to combat the population menace. Sperm impairing agents that can be applied topically for the prevention of fertility may offer one of the most promising contraceptive interventions. Spermicides have a long history of use as vaginal contraceptives, but no systematic investigation has been carried out. The rationale for using spermicides as vaginal contraceptives stems from the easy affordability, self controlled reversibility, minimal systemic exposure, reasonable effectiveness, need based usage, uninterrupted sexual act, and no requirement of medical supervision. Various vaginal contraceptives are currently available over the counter and most of these products are based on surfactants, with Nonoxynol-9 (N-9), taking the lead as an active spermicidal agent. However, frequent use of N-9 has been shown to cause detrimental effects on vaginal epithelium, making the users more prone to HIV and other microbial infections. Thus, an unanticipated void has been developed as no other agent is available to substitute surfactant spermicides in vaginal contraceptive products. This has provided the impetus for an increased emphasis on the development of safe, highly effective and inexpensive sperm impairing agents as vaginal contraceptives. In a Portfolio geared towards the development of new vaginal contraceptives, microbial factors have flared up as the most reliable alternative to the chemical/ detergent ingredients. Microorganisms are known to impede sperm motility, either by secreting extracellular products that immobilize the sperm or directly by agglutinating the spermatozoa. Corresponding factors responsible for immobilization are worth pursing for the development of a successful vaginal contraceptive device. In our laboratory in pursuit of a newer contraceptive agents sperm immobilizing factor (SIF ) has been extracted and purified from a strain of Staphylococcus aureus. SIF holds the great potential as contraceptive agent as it exhibited noteworthy sperm immobilizing and spermicidal effect in vitro. Given that, one cannot rely entirely on an in vitro spermicidal data to evaluate the vaginal potency of a new compound, an attempt was made to assess its contraceptive efficacy in mice. When different concentrations of SIF (2.5,5,10,25,50 and 100μg) were instilled in the vagina of female Balb/c mice as a single dose before mating, it was observed that SIF at a concentration of > 5 μg / animal rendered female mice infertile, while the mice receiving lower doses of SIF i.e. 2.5 μg became pregnant. These results highlighted that the SIF at the concentrations 5 μg and above incur a contraceptive effect in mice when applied intravaginally. Taking into consideration the potent antifertilizing activity of SIF it was formulated into gel in order to develop a new vaginal contraceptive formulation.
Audience Take Away:
- The audience will come to know about the development of newer vaginal contraceptive.
- These experimental studies can be further extrapolated to clinical studies.
- The newer contraceptive has been found to be quite safe as compared to vaginal contraceptives available in the market.
