Israeli scientists say they have hit upon a way of separating safe and unsafe molecules that will usher in “a new era of better and safer drugs and pesticides”.

Professors Yossi Paltiel of the Hebrew University of Jerusalem and Ron Naaman from the Weizmann Institute of Science say their “breakthrough technology” gives the power to create drugs with fewer unwanted side effects.

Outlining their findings in a new study published in Science on Thursday, the pair said they had been working on the problem for a decade, and had finally come up with a solution using magnets.

The most important molecules in biology are chiral molecules. “Chiral,” the Greek word for “hand,” describes molecules that look almost exactly alike and contain the same number of atoms but are mirror images of each another, meaning some are “left-handed” and others are “right-handed”.  This different “handedness” is crucial and yields different biological effects.

Understanding chiral differences is exemplified by the drug thalidomide.  Marketed to pregnant women in the 50’s and 60’s to ease morning sickness, it worked well under a microscope, but it is a chiral drug, and whereas its “right” chiral molecule provides nausea relief, the “left” causes horrible deformities in babies. The drug company producing it did not separate out the right and left molecules, with disastrous results.

The issue for scientists ever since has been how best to separate chiral molecules into their right- and left-handed components. Until now the processes have been expensive and relied on tailor-made approaches for each molecule.

In their paper, Paltiel and Naaman say they have now discovered a uniform, generic method that will let pharmaceutical and chemical manufacturers easily and cheaply separate right from left chiral molecules, using a method that uses magnets.

Chiral molecules interact with a magnetic substrate and line up according to the direction of their handedness, so “left” molecules interact better with one pole of the magnet, while “right” molecules interact better with the other one.

They said the technology will allow chemical manufacturers to keep the “good” molecules and to discard the “bad” ones that cause harmful or side effects.

“Our finding has great practical importance,” said Prof Naaman. “It will usher in an era of better, safer drugs and more environmentally-friendly pesticides.”

Currently only 13 percent of all chiral drugs are separated, even though America’s Food and Drug Authority (FDA) recommends that all chiral drugs be separated. In agro-chemicals, chirally-pure pesticides and fertilisers require smaller doses and cause less environmental contamination than their unseparated counterparts.

The universities said Paltiel and Naaman’s “simple and effective” chiral separation technique will lead to the production of better medical and agricultural products, including medicines, food ingredients, dietary supplements and pesticides.

“We are now transforming our science into practice,” said Paltiel. “Placing better medical and environmental products on the market is a win-win for industry and for patients.”

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