Reversible inhibition of sperm under guidance
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2007-12-15T02:22:26Z
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'''Reversible Inhibition of Sperm Under Guidance''' ('''RISUG'''), formerly referred to as '''SMA''', is the development name of a [[male contraceptive]] developed at [[IIT]] (Delhi) in [[India]] by Dr. [[Sujoy K Guha]]. It is currently undergoing Phase III clinical trials in India. It has been patented in India, China, Bangladesh and the United States.
== Mechanism of action ==
RISUG works by an injection into the [[vas deferens]], the vessel through which the [[Spermatozoon|sperm]] moves before [[ejaculation]]. In a matter of minutes, the [[Injection (medicine)|injection]] coats the walls of the vas with a clear [[gel]] made of 60 mg of the [[copolymer]] [[styrene]]/[[maleic anhydride]] (SMA) with 120 [[microlitre|µL]] of the solvent [[dimethyl sulfoxide]]. The copolymer is made by [[irradiation]] of the two [[monomer]]s with a dose of 0.2 to 0.24 [[Rad (unit)|megarad]] for every 40 g of copolymer and a dose rate of 30 to 40 rad/s. 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.[http://www.lib.utah.edu/epubs/undergrad/vol6/peterson.html] More recent research claims that this is not enough to explain the effect.
One explanation is that the polymer is an [[anhydride]], and [[hydrolization|hydrolizes]] in the presence of water in the spermatic fluid. Due to the breaking of a cyclic group, the polymer becomes a [[hydride]] and has a positive charge. This disturbs the negative charge of the sperm membrane on contact. (From {{US patent|5488075}})
Some theorize that the polymer surface has a negative and positive [[electric charge]] mosaic. The differential charge from the gel ruptures the sperm's [[cell membrane]] as it passes through the vas, stopping the sperm before they can start their journey to the [[ovum|egg]].[http://www.malecontraceptives.org/methods/risug.htm]
"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.
== Alleged Advantages ==
{{Inappropriate tone|date=December 2007}}
Some of the advantages, according to Dr. Guha {{Fact|date=August 2007|date=August 2007}}:
* '''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 [[pregnancy]] among their partners — and in that instance, the injection wasn't administered properly.
* '''Convenient''' - Neither [[sexual partner]] has to interrupt the throes of passion to use it — no more running to the bathroom and fumbling with various [[ointments]] and plastics.
* '''Non-surgical''' - The process, once it is refined and approved, will be operation-free. Men can leave the hospital immediately after an injection and resume their normal sex lives within a week.
* '''Long-lasting''' - According to Guha, a single 60 [[milligram|mg]] injection can be effective for at least 10 years.
* '''Few side effects''' - After testing RISUG on more than 250 volunteers, neither Guha nor other researchers in the field claim [[Adverse effect (medicine)|side effects]] more worrisome than a slight [[scrotal]] swelling in some men immediately following the injection which goes away after a few weeks, though [[#Controversy|there are also unconfirmed reports]] of kidney problems. These drawbacks, however, pale in comparison with those of contraceptive pills, which can cause health problems ranging from severe [[migraines]] to [[blood clots]].
* '''Reversible''' - The [[contraceptive]] appears to be reversible by flushing the vas deferens with another injection of [[dimethyl sulfoxide]] or [[sodium bicarbonate]] solution. (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.
**Unlike in a [[vasectomy]] (see [[Blood-testis barrier]]), the vas deferens is not completely blocked, the body doesn't have to absorb the blocked sperm, and sperm [[antibodies]] are not produced in large numbers, making reversal more feasible than [[vasovasostomy]].
== Controversy ==
The thoroughness of [[carcinogenicity]], [[teratogenicity]] and [[toxicity]] testing in clinical trials has been questioned. In October 2002, [[Indian health ministry|India's Ministry of Health]] aborted the clinical trials due to reports of [[human serum albumin|albumin]] in [[urine]] and scrotal swelling in [[Clinical trial#Phase III|Phase III trial]] participants. [http://infochangeindia.org/archives1.jsp?secno=3&monthname=December&year=2002&detail=T] The [[Indian Council for Medical Research]] noted that [[dimethyl sulfoxide]] used as a solvent for the injection is known to cause kidney damage. [http://indlaw.com/10D503BFE86F1141C20267C446BF604C] Although the ICMR has reviewed and approved the toxicology data three times, some [[United States]] researchers say that the studies were not done according to recent international standards.
RISUG was resubmitted for a new round of tests at a US lab, and was approved as non-mutagenic in July 2005. With this new stamp of approval, the path to continued Phase III trials in India became clear.
In March 2006, the ICMR announced that Phase III trials of RISUG could resume at 4 centers around India. The announcement of this progress led to renewed interest in RISUG. Unfortunately, little progress has been made since March. The research centers do not have enough of the RISUG compound to move forward with the trial. Marksans, the pharmaceutical company which has a manufacturing agreement with the inventor and the government, is now over a year past its initial April 2005 product delivery estimate. It is not clear why the delay continues.
Once this form of contraception is released into the market, it could displace the use of [[condom]]s. Unlike condoms, RISUG provides no protection against the spread of [[sexually transmitted diseases]]. A study, however, is underway to test the efficacy of RISUG as an anti-HIV agent, due to a hypothesis that the styrene maleic acid lowers pH to a level sufficient to destroy HIV in semen. [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15893119&dopt=Citation]
== External links ==
* {{US patent|5488075}}
* [http://www.malecontraceptives.org/methods/risug.htm Detailed information from Male contraceptives.org]
* [http://www.malecontraceptives.org/methods/risug_refs.htm Studies of RISUG Experimental male contraceptive 1976-2004]
* [http://www.gumption.org/mcip/paper.html#vas SMA]
* [http://icmr.nic.in/annual/rh.htm ICMR Website]
* [http://icmr.nic.in/annual/hqds2004/reproductive.pdf ICMR 2004 Anuual Report]
* [http://www.hindustantimes.com/news/181_1263437,000600010003.htm Hindustan Times]
* [http://www.grist.org/news/maindish/2003/08/13/sperminator/ The Sperminator in Grist Magazine]
* [http://www.malecontraceptives.org/methods/articles/indiatoday_risug.html India Today Article]
* [http://www.expressindia.com/ie/daily/20001026/ina26068.html Indian Express Article]
* [http://web.archive.org/web/20040810165830/http://www.malecontraceptives.org/methods/articles/nationalpost_risug.html Canadian Doctor implements RISUG]
* [http://infochangeindia.org/archives1.jsp?secno=3&monthname=December&year=2002&detail=T Country’s first male contraceptive aborted] (October 2002)
* [http://www.expressindia.com/ie/daily/20001026/ina26068.html ICMR takes a shot at a male contraceptive] (October 2000)
* [http://health.groups.yahoo.com/group/malecontraceptives/message/105 An interpretation of "Status of Spermatogenesis and Sperm Parameters in Langur Monkeys Following Long-term Vas Occlusion With Styrene Maleic Anhydride"]
[[Category:Andrology]]
[[Category:Experimental methods of birth control]]
[[Category:Contraception for males]]
[[Category:Bioengineering]]