Research is at first, but Chinese scientists say they use bartender tricks to break new, reversible male contraception.
In rats, the method successfully kept sexually active men from impregnating women for more than two months.
"The two most commonly used male contraceptives are condom and vasectomy," noted a team led by Xiaolei Wang from Nanchang University. "Safe and Reversible Medium Term [2 to 20 weeks] urgently requires a contraceptive method between a single condom and constant contraception. "
Their possible solution was inspired by colorful cocktails, which were often invented by bartenders. In these mixtures liquids form different layers in the glass. But by mixing or heating, the layers combine into a single liquid.
A promising but long way
So, the Wang group developed a male contraceptive form in which the layers of material are injected into the ridge deferences – the channel through which the sperm travels from the testicles to the urethra – to block it.
Blocking continues until the heat applied to the blocked area causes the layers to mix, shatter, and thus remove the windshields.
The Chinese group argues that this method is being tested in male rats by injecting four layers of material into iron deferens. The successive layers were: hydrogel, which forms a physical barrier to sperm; gold nanoparticles that heat up when exposed to infrared radiation; ethylenediaminetetraacetic acid (EDTA), a chemical that disrupts hydrogel and also kills semen; and another layer of gold nanoparticles.
While liquid layers in the summer deferens were in place, male rats were not impregnated for more than 2 months, Wang reported in the magazine on January 30 ACS Nano.
But when the researchers shone for a few minutes on a close infrared light on the male rat, the layers were mixed and dissolved, and the male rats were able to impregnate the women again. It offers men an "effective and reversible way to fill the current lack of a medium-term contraceptive strategy".
But, "although our method is promising, there is still a lot to do in practice," said the Chinese team. "To ensure material safety, more animal testing is needed," they said, and results in animals often do not cause people.
One US fertility expert agreed that much more research was needed.
"This study is a very preliminary insight into injectable male contraception," said Dr. Mary Rausch of Northwell Health Fertility in Manhasset, New York. "Although this is a long way to be ready for the trial or, of course, for people, it would be a medical breakthrough if it happened.