pro 2000 pro 2000 pro 2000 is an experimental vaginal microbicide which has been proposed as a preventive medicine for reducing the risk of contracting hiv. it has never been recommended as an effective medicine to be used for any purpose. some clinical trials have shown that under some conditions it may provide some protection against hiv. pro 2000clinical dataother names2-naphthalenesulfonic acid, sodium salt, polymer with formaldehydeidentifiers iupac name sodium 2-naphthalenesulfonate, polymer with formaldehyde cas number29321-75-3chemspidernoneniaid chemdb032942comptox dashboard (epa)dtxsid401011472 echa infocard100.111.201 chemical and physical dataformula(c10h8o3s.ch2o.na)xmolar massapproximately 5 kg/mol history endo pharmaceuticals manufactures the drug. efficacy animal testing studies done on macaques have shown that pro 2000 is effective in preventing the transmission of hiv. other studies have given supportive evidence that the product is safe in humans and would be an appropriate candidate for testing. a phase iii clinical trial of 9385 women in sub-saharan africa showed that pro 2000 was not effective in preventing transmission of hiv.