Much research is being done to develop new forms of contraception, although at a seemingly glacial pace. A study from North Carolina State University, published in Bioactive Materials, may have just unveiled a breakthrough in this field. The discovery comes in the form of a new contraceptive gel that has proven to be a triple threat: preventing pregnancy, inhibiting viruses, and increasing libido in rat studies. "The trifunctional contraceptive gel we created yielded higher contraceptive success rates than those on the market, and has great potential for improving the safety and quality of sexual intercourse," said Professor Ke Cheng, an author of the study in a statement.
The gel works by using three ingredients, all already approved by the FDA. Gossypol is a spermicide that inhibits sperm motility, with previous research highlighting its potential as a contraceptive. Tenofovir is an antiviral that inhibits the transcription and replication of viruses and is already used to reduce HIV transmission. Nitroglycerin helps expand vascular smooth muscle and therefore increases local blood flow, and is considered an effective erectile enhancer.
Currently available spermicidal gels containing nonoxynol-9 are only around 72% effective in practice according to Planned Parenthood, compared to 91% for the pill and 85% for condoms. They also have the disadvantage of not protecting against STIs. In fact, long term use of these gels can destroy normally occurring bacteria in the vagina and cause irritation and damage, potentially increasing the risk of contracting STIs.
The new gel developed in this study has a pH of 4.5, which is the same as the vagina, making it compatible. It was also demonstrated not to damage vaginal epithelial cells and did not seem to impact liver or kidney function. The authors also state in the paper that the gel was “in a compact and porous structure that is benefit for degradation and clearance in the vagina,” and that “properties of the gel demonstrated that it would be a good sexual lubricant.”
The ability of a virus to infect vaginal epithelial cells was examined with and without the gel. The authors of the paper say that the results indicate that the gel is “likely able to interfere with the viral infection process by releasing functional agents, and has the potential to prevent STD transmission during sexual intercourse.”
To test how spermicidal the gel was, the researchers loaded pipettes with pig sperm. They then covered the pipette tips with the gel and shot the sperm onto a glass slide to mimic ejaculation. Upon observation, the sperm cells had lost their ability to move forwards.
The gel was applied to the vaginas of female rats in estrous before they were placed in a cage with fertile male rats. There were no pregnancies 22 days after successful mating in the group that used the new gel, compared to rats in the control group, all of which got pregnant. One pregnancy occurred in the group that was given a gel that is already on the market.
The gel was also applied to the penises of male rats, after which a female rat was added to their cage. It was observed that the gel increased the number of times the rats mated, and significantly reduced the time it took for the rats to get down to business. The researchers also saw that the gel helped the penis become erect, with more erections occurring over the 20-minute observation period. This may mean that the new gel could also help with erectile dysfunction.