RISUG (reversible inhibition of sperm under guidance)--an antimicrobial as male vas deferens implant for HIV free semen.

HIV transmission from the male to the female is a major health problem. A hypothesis proposing an intra vas deferens implant of an antimicrobial compound to prevent the infection spread is presented. Mechanisms of action for the inhibition could include inactivating HIV in sperms passing through the vas deferens; drug release from the implant to destroy HIV entering into semen from genital structures distal to the vas deferens; and sperm acrosome released hyaluronidase mediated reabsorption of HIV. A subcomponent of the implant flowing along sperm pathway may have a role in reducing the entry of HIV from a positive female into penile tissue. A new drug RISUG (reversible inhibition of sperm under guidance) presently undergoing clinical trials for its contraceptive effect in the male (because it disrupts the sperm acrosome by an electrical charge and pH lowering effects) has also antimicrobial action. The drug being a combination of styrene maleic anhydride (SMA) and dimethyl sulfoxide (DMSO) on being injected into the lumen of the vas deferens produces styrene maleic acid thereby lowering pH; induces electrochemical action leading to a stable electrical charge generation; releases mandelic acid; and induces acrosome reaction in sperms with consequent release of hyaluronidase and sperm inactivation. Moreover, one time administration into the lumen of the vas gives long term action. All these phenomena very well match with the needs for HIV clearance of semen and hence RISUG is here proposed as a possible candidate material for the HIV inhibiting vas deferens implant when delivered in below contraceptive threshold dosage. For experimental validation, after obtaining data on the semen HIV load under control conditions in the HIV positive males inducted into the study, 30 mg of SMA in 120 microl of DMSO (contraceptive dose being 60 mg SMA+120 microl DMSO) is to be injected into vasa deferens bilaterally. Thereafter at intervals of one month the viral load needs to be determined in semen obtained either by masturbation or in lubricant free condom at intercourse - the method of collection remaining the same throughout for a particular subject. A significant reduction in the semen viral load following RISUG administration will validate the hypothesis. Speculated reduced female to male HIV transmission is more difficult to test. Nonspecific indications will come from a population study of the incidence of RISUG treated men becoming HIV positive as compared to that in the general population.