Researchers from North Carolina State University have created a trifunctional contraceptive gel that contains spermicidal, anti-viral and libido-enhancing agents in one formulation. When tested in a rat model, the gel both enhanced male libido and prevented pregnancy in 100% of cases, as compared to an average 87% effective rate with a commercially available contraceptive gel.
"We are using three pharmacological agents in a new formulation," says Ke Cheng, Randall B. Terry, Jr. Distinguished Professor in Regenerative Medicine at NC State's College of Veterinary Medicine, professor in the NC State/UNC Joint Department of Biomedical Engineering and corresponding author of a paper describing the work. "Our hope is that this trifunctional contraceptive gel could further enhance the safety and quality of sexual intercourse."
The new carbomer-based gel contains the contraceptive gossypol, the antiviral tenofovir and nitroglycerin to stimulate blood flow.
Cheng and his team first tested the gel in vitro to determine spermicidal and antiviral efficacy, as well as toxicity to vaginal epithelial cells. At 10 micrograms per milliliter gossypol concentration, the gel was effective in killing almost 100% of pig sperm - used for in vitro testing - in 30 seconds. Lower concentrations were equally effective by 180 seconds.
They also tested the gel in vitro against a lentivirus and found that it did have an inhibitory effect, indicating its potential to reduce transmission of sexually transmitted diseases. The gel was also shown not to be damaging to epithelial vaginal cells, as cell damage in treated cells was not significantly different from non-treated, or control cells.
Next, the researchers looked at contraceptive effects in a rat model. Eighteen female rats were divided into three groups: one that received the new gel; one that received a common commercially available contraceptive gel containing nonoxynol9; and a control. The females in the trifunctional gel group had no pregnancies, as opposed to one pregnancy in the nonoxynol9 group.
The team also tested the gel's effect on male rats' libido and erectile function. Rats that received the gel mated more frequently and with shorter incubation periods than those that did not.
"The trifunctional contraceptive gel we created yielded higher contraceptive success rates than those on the market," says Cheng, "and has great potential for improving the safety and quality of sexual intercourse."
The research appears in Bioactive Materials.
###
Note to editors: An abstract follows.
"A trifunctional contraceptive gel enhances the safety and quality of sexual intercourse"
DOI: 10.1016/j.bioactmat.2020.11.031
Authors: Mengjie Xie, Junlang Li, Sichen Zhang, Dashuai Zhu, Xuan Mei, Zhenzhen Wang, Xiao Cheng, Zhenhua Li, Ke Cheng, North Carolina State University; Shaowei Wang, Chinese Academy of Medical Sciences Published: Online Dec. 3, 2020 in Bioactive Materials
Abstract:
Current contraceptive methods come with a number of drawbacks, including low efficacy, in the case of commercial contraceptive gels, and a reduction in the quality of sexual intercourse, in the case of condoms. Adding pharmacologically-active agents to contraceptive gels holds the potential to improve sexual experience, and hardbor safety and hygiene. In this study, we fabricated a carbomer-based contraceptive gel consisting of three agents: tenofovir, gossypol acetate, and nitroglycerin (TGN), with pH adjusted to 4.5 (to be compatible with the vagina). In vitro, the gossypol component of the contraceptive gel proved to be an effective spermicide. When the concentration of gossypol acetate was 10 mg/ml, the spermicidal ability reached 100% after 30 s. In addition, tenofovir in the gel significantly inhibited lentiviral transfection efficiency in cell-containing media. In 6 pairs of rats, the gel successfully prevented all females from conceiving after successful mating. Moreover, increased sexual frequency and enhanced erection, which were promoted by the nitroglycerin in the components, were observed in male rats that had the gel applied to their penises. This novel TGN contraceptive gel yielded a higher contraceptive success rate than that of the commercial contraceptive gel (Contragel®). In addition, it has the added benefits to prevent sexually transmitted diseases and improve male libido and erectile function during sexual intercourse. Combining three FDA-approved and marketed agents together, our trifunctional TGN gel has a great potential for further translation and commercialization.
Journal
Bioactive Materials