Scientists in China are designing a gel containing an experimental drug which they hope can reduce HIV infections in women.

The search for such a prophylaxis is gaining urgency in China with sex becoming the number one mode of HIV transmission and new HIV infections rising sharply among Chinese women.

The gel acts as an "entry inhibitor" — blocking the human immunodeficiency virus (HIV) from gaining entry into host cells, Chen Zhiwei, director of the AIDS Institute at the University of Hong Kong, said in an interview.

The experimental treatment drug used in this gel has passed animal tests and a small safety test in people, Chen said.

Chen and his colleagues are now preparing to convert it into a microbicide - a gel that is inserted into the vagina or rectum before sex to prevent transmission of HIV, which causes AIDS.

"We are using it as a microbicide, to be used topically to prevent transmission in women. Women are disadvantaged during sexual intercourse, that's why we try to provide some means to women to control their lives," Chen said.

The Chinese gel will undergo three clinical trials, with the last taking place in an area with high HIV incidence rates.

"It will have thousands of random participants ... We need to prove it is safe (Phase 1) and shows efficacy (Phase 2), then we ask the government to support the larger study," Chen said.

A group of scientists working on another gel containing Gilead Sciences AIDS drug tenofovir announced in July that it reduced HIV infections in women by 39 percent in a study in South Africa.

Chen is working with scientists at Nanjing University and the Shanghai Institute of Planned Parenthood Research, among others.

Of the 740,000 people living with HIV/AIDS in China in 2009, 59 percent were infected through sex; with 44.3 percent infected through heterosexual sex and 14.7 percent via male-to-male sex, according to a report issued in May by China's health ministry and the Joint U.N. Programme on HIV/AIDS.

Of the total figure of 740,000, 30.5 percent are women.

The proportion of women becoming infected has also soared, with the male/female ratio narrowing from 11:1 in 1996 to 1.4:1 in 2009 in some provinces, according to Chinese press reports.