Researchers have found that a single injection of a new contraceptive called Vasalgel can provide males condom-free sex for a year, yet reversible male contraceptive. Currently men have few options for reproductive control, including condoms and vasectomy. Condoms are widely available and useful in preventing disease when used correctly, but have an 18 percent yearly pregnancy rate in typical use.

Vasectomy is effective, but must generally be considered permanent. There are no long-acting, reversible contraceptives currently available for men.

"Results from our study in rabbits were even better than expected," said lead author of the study Donald Waller, professor at University of Illinois at Chicago, US. "Vasalgel produces a very rapid contraceptive effect which lasted throughout the study due to its unique hydrogel properties. These features are important considerations for a contraceptive product to be used in humans," Waller noted.

Vasalgel, developed by US-based non-profit company Parsemus Foundation, consists of styrene-alt-maleic acid (SMA) dissolved in dimethyl sulfoxide and could be the first long-acting, non-hormonal, potentially reversible male contraceptive to reach the market, the researchers said.

After the gel was injected into the duct which conveys sperm from the testicle to the urethra - the vas deferens - of 12 rabbits, semen analysis revealed that 11 rabbits were azoospermic, having no quantifiable sperm in their semen at all.

"Contraceptive development is a hugely expensive project. But this is not just another early-stage lead, we're so close on this one. It's time to finish the job we've started," Elaine Lissner, executive director of Parsemus Foundation said.

Human trials will begin later this year, while developers claims that it could be available to the public as early as 2018.

By Premji