April 28, 2008

Purdue expert says U.S. has low risk of receiving contaminated drugs

"Tragic events such as the recent deaths and illnesses caused by contaminated heparin are alarming, but are extremely rare," says Stephen R. Byrn, the Charles B. Jordan Professor of Medicinal Chemistry and head of the Department of Industrial and Physical Pharmacy. "The majority of drugs distributed in the United States contain elements manufactured outside the country. There is a rigorous regulatory and testing process before these elements are incorporated into a final drug product."

The U.S. Food and Drug Administration's mandated good manufacturing practices are key to maintaining pharmaceutical quality. The most common ways drugs are contaminated are through residues on materials or misuse of equipment in the drug-making process, he says.

"If something goes wrong during the mixing of chemical reagents or the reactions necessary to create the drug substance, that can create impurities in the drug," Byrn says. "If the drug substance or reagents are not stored properly, the drug could degrade. If a container used has residues of another chemical, it could cause cross-contamination."

In addition, having the correct equipment and using it properly is very important when dealing with chemical reactions and pharmaceutical manufacturing, he says.

"Using the wrong equipment is like using a blender instead of a mixer to make bread," he says. "The loaf of bread will be similar but not quite right. The equipment could create too much heat, which could alter the manufacturing process that produces the drug."

There are two main steps in making a drug: manufacture of the drug substance and manufacture of the drug product. The second step is usually performed in the United States, but the first is often outsourced.

"The drug substance is the actual therapeutic agent or chemical compound," Byrn says. "During the past 20 years, firms outside the United States have taken over this manufacturing step. China, India, Ireland, Singapore and Slovenia have become the main sources. It is much less expensive, and the cost can be one-half or even one-tenth of the cost of U.S. manufacturing."

The foreign-manufactured drug substance is then brought to the United States and incorporated into the drug product - the actual tablet or injection a person takes.

"U.S. firms do careful testing of the drug substance before putting it into the drug product that is administered," Byrn says. "The drug substance is run through many tests to check for any impurities of the product. Contaminants are typically known and easily identified through these tests. However, as seems to be the case with the heparin, sometimes an unknown contaminant goes undetected."

The Food and Drug Administration requires U.S. pharmaceutical companies to use registered and approved manufacturing sites. It also maintains regulatory power over any offshore facilities owned by U.S. companies. However, it is difficult to make frequent visits and inspections of facilities in other countries, Byrn says.

"Most of the firms in other countries are owned by U.S. companies, and representatives are on site to ensure good manufacturing practices are followed," he says. "However, some are not U.S. owned and fall under foreign regulatory law, which in some countries is still evolving and less controlled."

The United States has greater control and far less risk of unsafe pharmaceutical products than any other country, Byrn says.

"Pharmaceutical firms take a lot of care to make a product they would be willing to give to their grandmothers, but problems can occur even with a strong regulatory system in place."

Writer: Elizabeth Gardner, (765) 494-2081, ekgardner@purdue.edu

Source: Stephen Byrn, (765) 714-2808, Stephen.byrn@verizon.net

Purdue News Service: (765) 494-2096; purduenews@purdue.edu

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