Reversible inhibition of sperm under guidance

RISUG (formerly referred to as SMA) is a contraceptive method which was invented in India; a third world country where all the trials have been performed. Because of this, some scientists state that there are safety issues which have not been solved.

RISUG stands for Reversible Inhibition of Sperm Under Guidance. It is the development name of a male contraceptive, which came into being through about 25 years of research and testing. The technique was developed at IIT(Delhi) in Indiaby Dr.Sujoy K Guha. It has been patented in India, China, Bangladesh and the US.

RISUG works by an injection into the vas deferens, the vessel through which the spermmoves before ejaculation. In a matter of minutes, the injectioncoats the walls of the vas with a clear gelmade of 60 mg of the copolymerstyrene/maleic anhydride(SMA) with 120 µL of the solvent dimethyl sulfoxide. The copolymer is made by irradiationof the two monomerswith a dose of 0.2 to 0.24 megaradfor every 40 g of copolymer and a dose rate of 30 to 40 rad/s. The source of irradiation is cobalt-60gamma radiation.

The effect the chemical has on sperm is not completely understood. Originally it was thought that it lowered the pHof the environment enough to kill the sperm.[1] More recent research claims that this is not enough to explain the effect.

One explanation is that the polymer is an anhydride, and hydrolizesin the presence of water in the spermatic fluid. Due to the breaking of a cyclic group, the polymer becomes a hydrideand has a positive charge. This disturbs the negative charge of the sperm membrane on contact. (From U.S. Patent 5,488,075)

Some theorize that the polymer surface has a negative and positive electric chargemosaic. The differential charge from the gel ruptures the sperm's cell membraneas it passes through the vas, stopping the sperm before they can start their journey to the egg.[2]

?Within an hour, the drugs produce an electrical charge that nullifies the electrical charge of the spermatozoa, preventing it from penetrating the ovum,? Dr Guha said.

Men can leave the hospital immediately after an injection and resume their normal sex lives within a week.

Advantages

Some of the advantages, according to Dr.Guha:

• Neither sexual partnerhas to interrupt the throes of passion to use it ? no more running to the bathroom and fumbling with various ointmentsand plastics.
• The process, once it is refined and approved, will be completely non-surgical.
• It's long-lasting. According to Guha, a single 60 mg injection can be effective for at least 10 years.
• After testing RISUG on more than 250 volunteers, neither Guha nor other researchers in the field have found side effects more worrisome than a slight scrotalswelling in some men immediately following the injection. This swelling goes away after a few weeks. Compare that to the Pill, which even today can cause health problemsranging from severe migrainesto blood clots.
• It works. Of all the men who've had the RISUG injection (and 15 of the 250 had it more than 10 years ago), there has been only one unplanned pregnancyamong their partners ? and in that instance, the injection wasn't administered properly.
• The contraceptiveappears to be reversible by flushing the vas with another injection of dimethyl sulfoxideor sodium bicarbonatesolution. (The sodium bicarbonate solution cannot be used as the solvent in the initial injection since it would neutralize the positive charge effect.) To date, reversing the procedure has been tried only on non-human primates, but among them, it's been reversed successfully multiple times.

• Since the vas is not completely blocked, the body doesn't have to absorb the blocked sperm, and sperm antibodiesare not produced in large numbers as they are for a vasectomy, making reversal more feasible.

Controversy

The thoroughness of carcinogenicity, teratogenicityand toxicitytesting in clinical trials has been questioned. In October 2002, India's Ministry of Health aborted the clinical trials due to reports of albumenin urineand scrotal swelling in Phase III trialparticipants. [3] The Indian Council for Medical Researchnoted that dimethyl sulfoxideused as a solvent for the injection is known to cause kidney damage. [4] Although the ICMR has reviewed and approved the toxicology data three times, some US researchers say that the studies were not done according to recent international standards.

External links

• U.S. Patent 5,488,075
• Detailed information from Male contraceptives.org
• Studies of RISUG Experimental male contraceptive 1976-2004
• SMA

• ICMR Website
• ICMR 2004 Anuual Report
• Hindustan Times
• The Sperminator in Grist Magazine
• India Today Article
• Indian Express Article
• Canadian Doctor implements RISUG

• Country?s first male contraceptive aborted(October 2002)
• ICMR takes a shot at a male contraceptive(October 2000)
• An interpretation of "Status of Spermatogenesis and Sperm Parameters in Langur Monkeys Following Long-term Vas Occlusion With Styrene Maleic Anhydride"

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