Jay A. Bua helped another company develop a $100 million business in a gel that delivers medicine through the skin. Now, he is trying to repeat the success story on his own.

Working in the 1990s as head of U.S. operations for Besins International, a Belgian maker of gel drugs, Bua conceived AndroGel to treat severely low testosterone levels among young and middle-aged men, a problem that leads to effects such as loss of dexterity, muscle strength and libido.

Since its 1999 launch, Bua said, AndroGel has catapulted the testosterone replacement therapy market from about $30 million a year to $230 million a year.

Bua decided to head off on his own in early 2002, founding Ascend Therapeutics Inc. of Herndon. The company licensed the gel technology from Besins with the right to develop new drugs and sell them to pharmaceutical companies.

The transparent alcohol-based gel is applied through the skin, delivering medicine through blood circulation. This is especially good for people who can't take drugs orally or those who suffer side effects when the drug isn't near the area in the body it's supposed to help, Bua said.

"It's safer and potentially more effective," said Bua, 55, who has 20 years of experience in the pharmaceutical industry.

One product Ascend Therapeutics is developing would treat severe breast pain for women in their thirties and forties through a gel applied to the breast. About 11 million women suffer from breast pain, said Suzanne N. Richardson, the company's chief financial officer and senior vice president of business development. TamoGel, now in testing, is being studied as a way to reduce breast tissue density, which would lessen pain and also make mammograms easier to read and breast cancer easier to spot.

The other product, also in the testing phase, is Andrin, a second-generation AndroGel-like drug that would help raise testosterone levels for older men with less risk than other products of damaging the prostate gland as a side effect. It would be applied to the upper arms and shoulders.

By year's end, Bua said, Ascend hopes to partner with a large pharmaceutical company that can help market its products once they are federally approved for use.

Dana C. Hilt and Jay A. Bua discuss clinical trial results for TamoGel with their colleagues in France and England via a conference call. Ascend Therapeutics is developing a gel product that would treat severe breast pain.