Dextran sulfate is one of the older agents known to block HIV transmission in vitro (i.e., test tube). When it was tested in patients infected with HIV, however, it didn't reduce the blood-circulating levels of the virus. This often happens with potential anti-HIV agents, which seem to work well in vitro, but then fail in clinical testing.

Still, it's entirely possible that agents like dextran sulfate might be effective in blocking the HIV infection of mucosal membranes during sexual intercourse. For AIDS researchers, this is something of the holy grail, if they could develop a "chemical" barrier as an adjunct to the "physical" barrier of condoms. This is especially important in the third-world, where women often cannot induce their male partners to use condoms. Initially, it was thought that the spermicide nonoxynol-9 would fit this role, as it is very efficient in killing the AIDS virus in vitro. Nevertheless, nonoxynol-9 also has the unfortunate habit of inflamming mucosal membranes, actually making them more susceptible to HIV transmission during sex. This was found out only after years of clinical testing.

You'll note that the clinical testing of dextran sulfate will be conducted by British scientists, not Americans. That is not very surprising, since the George W. administration is committed to stopping HIV transmission through tutorials/lessons in abstinence. Much of the government funding has been cut off for promising research in anti-HIV gels. Gee, I guess this turned into a political comment. Sorry about that...

-- Modified on 3/27/2004 8:33:11 AM

There's a company called "Biosyn" who is working on a gel that prevents all STDs.  Check out their website.