Researcher Creates Drug Purity Analysis Method For Pharmaceutical Companies

FAYETTEVILLE, Ark. - A University of Arkansas professor has created a monitor that can detect potentially dangerous impurities in pharmaceutical products during production and send the impure material back through the production line. This both creates a safer product and increases the drug’s production efficiency, lowering costs for companies and consumers alike.

Don Bobbitt, associate dean for research in the Fulbright College of Arts and Sciences and professor of chemistry, and graduate student Sean Linder will present their work at the National Science Foundation’s Center for Process Analytical Chemistry meeting on Tuesday, Nov. 7, in Seattle, Wash.

When researchers create a drug, their product often has an almost identical molecular twin, known as an enantiomer. The enantiomer physically and chemically resembles the pharmaceutical product, except that it reacts differently to light and does not function in the same way the drug does.

For many years, researchers thought that these twin-like enantiomers were harmless filler, but some have proved to be the equivalent of "evil twins," causing severe birth defects or other health problems. Since these findings, the Food and Drug Administration now requires pharmaceutical companies to know which enantiomers they have produced, to know their purity in the product, and to determine any potential side effects of the inactive enantiomer.

"You have to be very particular about enantiomers," Bobbitt said.

Pharmaceutical companies would prefer to do away with the wrong enantiomers altogether, but common chemical detection devices can’t distinguish between enantiomers - the molecules only differ physically in their ability to bend or polarize light.

Bobbitt and Linder have created a machine that uses a column, an ultraviolet detector and a polarimeter to monitor the purity of a drug or chemical as it is purified. The column separates out the materials produced based on molecular size or other physical or chemical properties. The ultraviolet detector measures how much of the drug is present. The polarimeter enables distinction between enantiomers, since they polarize light differently, and this allows the "twins" to be separately analyzed prior to further processing.

When the polarimeter detects the undesirable enantiomer, the detector uses a central processing unit and a switching valve to send the impure product back to the purification stage and repeats the whole process until it yields the maximum amount of purified product possible. The same central processing unit tells the switching valve to send the purified, desired enantiomer to a place where the final product can be packaged.

"The companies are picking up about half of what they would have thrown away every time," Bobbiitt said.

Several international pharmaceutical companies have collaborated with Bobbitt on this project, including Johnson and Johnson Pharmaceutical, Norvatis and PDR-Chrial, Inc.

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