STOCKHOLM, Oct 10: A trio of US and Japanese chemists whose “life and death” separation of molecules helped drug firms produce safer and cheaper medicine for ills ranging from Parkinson’s disease to the common flu won the Nobel Prize for chemistry here on Wednesday.

William Knowles and K. Barry Sharpless, both of the United States, along with Ryoji Noyori of Japan, were awarded the prize in recognition of their work developing “catalytic asymmetric synthesis,” a process by which critical drug ingredients are produced selectively and purely.

“The results of their basic research are being used in a number of industrial syntheses of pharmaceutical products such as antibiotics, anti-inflammatory drugs and heart medicines,” the Royal Swedish Academy of Sciences said in its citation.

Knowles, 84, is a retired former chemist with the St. Louis, Missouri-based US agrochemical giant Monsanto Company. Noyori, 63, teaches chemistry at Nagoya University in Japan. And Sharpless, 60, is a chemistry professor at the Scripps Research Institute in La Jolla, California.

At the heart of their work is the process of chemical synthesis that is used by pharmaceutical companies to manufacture specific molecules in large quantities for use in common drugs.

Most of those molecules occur naturally in two slightly different forms that mirror each other much in the way a left hand mirrors a right hand. Often however only one of these forms is useful in a drug while the other can be harmful to human health.

Dangers represented by use of the wrong molecule were thrust into tragic relief by the drug thalidomide which was introduced in the early 1960s. While one form of the key molecule in that drug reduced nausea in pregnant women, its other form caused birth defects in what became known as “thalidomide babies.”

This year’s Nobel Chemistry Prize laureates discovered ways to catalyze, or accelerate, production of specific molecules in such a way that yielded only the desired form of that molecule and discarded the useless or dangerous specimens.

Knowles was credited with research that led to an industrial process for production of the drug L-DOPA used in treating Parkinson’s disease. Noyori, the third Japanese to win the Nobel Prize for Chemistry, developed that work. Sharpless was cited for breakthroughs in a related process.—AFP