Reversible inhibition of sperm under guidance

Reversible inhibition of sperm under guidance (RISUG), formerly referred to as the synthetic polymer styrene maleic anhydride (SMA), is the development name of a male contraceptive injection developed at IIT Kharagpur in India by the team of Dr. Sujoy K. Guha. Phase III clinical trials are underway in India, slowed by insufficient volunteers. It has been patented in India, China, Bangladesh, and the United States. A method based on RISUG, Vasalgel, is currently under development in the US. However there has been little or no progress in terms of bringing the product to market. Reversible inhibition of sperm under guidance (RISUG), formerly referred to as the synthetic polymer styrene maleic anhydride (SMA), is the development name of a male contraceptive injection developed at IIT Kharagpur in India by the team of Dr. Sujoy K. Guha. Phase III clinical trials are underway in India, slowed by insufficient volunteers. It has been patented in India, China, Bangladesh, and the United States. A method based on RISUG, Vasalgel, is currently under development in the US. However there has been little or no progress in terms of bringing the product to market. RISUG works by an injection into the vas deferens, the vessel through which the sperm moves before ejaculation. RISUG is similar to vasectomy in that a local anesthetic is administered, an incision is made in the scrotum, and the vasa deferentia are injected with a polymer gel (rather than being cut and cauterized). In a matter of minutes, the injection coats the walls of the vasa with a clear gel made of 60 mg of the copolymer styrene/maleic anhydride (SMA) with 120 µl of the solvent dimethyl sulfoxide. The copolymer is made by irradiation of the two monomers with a dose of 0.2 to 0.24 megarad for every 40 g of copolymer and a dose rate of 30 to 40 rad/s. Dr P.Jha a Senior scientist worked on Effect of gamma dose rate and total dose interrelation on molecular designing and biological function of polymer The source of irradiation is cobalt-60 gamma radiation. The effect the chemical has on sperm is not completely understood. Originally it was thought that it lowered the pH of the environment enough to kill the sperm. More recent research claims that this is not enough to explain the effect. Professor S. K. Guha theorizes that the polymer surface has a negative and positive electric charge mosaic. Within an hour after placement the differential charge from the gel will rupture the sperm's cell membrane as it passes through the vas, deactivating it before it can exit from the body. Sujoy K. Guha developed RISUG after years of developing other inventions. He originally wanted to create an artificial heart that could pump blood using a strong electrical pulse. Using the 13-chamber model of a cockroach heart, he designed a softer pumping mechanism that would theoretically be safe to use in humans. As India's population grew throughout the 1970s, Guha modified his heart pump design to create a water pump that could work off of differences in ionic charges between salt water and fresh water in water treatment facilities. This filtration system did not require electricity and could potentially help large groups of people have access to clean water. India however decided that the population problem would be better served by developing more effective contraception. So Guha again modified his design to work safely inside the body, specifically inside the male genitalia. The non-toxic polymer of RISUG also uses differences in the charges of the semen to rupture the sperm as it flows through the vas deferens. Intellectual property rights to RISUG in the United States were acquired between 2010–2012 by the Parsemus Foundation, a not-for-profit organization, which has branded it as Vasalgel. Vasalgel, which has a slightly different formulation than RISUG, is currently undergoing successful animal trials in the United States. Initially, it was hoped that human trials would commence by the end of 2013 and become available to within a few years, but the Parsemus Foundation has encountered delays, and human clinical trials have yet to be initiated.