A new drug-releasing implant could prevent transmission of the human immunodeficiency virus (HIV) from a man to a woman, claims a research team from the School of Medical Science and Technology of the Indian Institute of Technology, Kharagpur.

The implant, called RISUG (reversible inhibition of sperm under guidance), could be injected in vas deferens, the tube that carries sperm from scrotum to urethra. "In vas deferens, RISUG releases antimicrobial compounds, which destroy virus particles in the semen,' says Sujoy K Guha, who led the research team. The findings of the study were published in a recent issue of Medical Hypotheses (Vol 65, No 1).

RISUG is a chemical complex of styrene maleic anhydride and dimethyl sulphoxide.