Repurposing companies experiment with unintended uses for pharmaceuticals.

Byline: Tricia Bishop

Nov. 20--What do Viagra and Silly Putty have in common?

Both started out as something else.

In 1944, Silly Putty was a failed attempt to make a synthetic rubber for soldiers' boots and airplane tires, but it found fame and fortune after someone thought to package it in plastic eggs and sell it as a toy in 1949. Viagra, also known as the "little blue pill," was developed in the early 1980s as a chest pain treatment, but it found its niche elsewhere in the 1990s.

"It didn't turn out to be as effective for its original purposes as it needed to be," said Kate Robins, a spokeswoman for Viagra's creator Pfizer Inc., based in New York. "But it demonstrated potential for male erectile dysfunction, and that use for that compound is pretty well known."

Inventors have a long history of turning losers into winners by changing their focus, and that's particularly true within the pharmaceutical industry, where some companies maintain in-house teams to find new uses for stalled or aging drugs. More recently, companies have sprung up specifically to investigate possible promising uses for drug experiments that didn't succeed as planned. These specialty companies -- known as repurposing, reprofiling or repositioning -- acquire drugs from others to develop themselves or provide contract services to existing businesses.

Industry experts say that roughly three dozen such companies have developed over the last…