3-D MAPPING: Terahertz technology detects counterfeit drugs

Researchers at TeraView (Cambridge, England) are using terahertz technology to help regulatory authorities, law-enforcement agencies, and the pharmaceutical industry screen for counterfeit drugs. The company presented initial results from a recent study run jointly with the U.S. Food and Drug Administration (FDA; St. Louis, MO) at an International Foundation Process Analytical Chemistry (IFPAC) conference on pharmaceutical manufacturing technologies. The study detected variations in the thickness and uniformity of tablet coatings from products bought over the Internet.

According to the World Health Organization (WHO), the market for counterfeit drugs worldwide is estimated at around $43 billion. The scale of the problem has led WHO, along with more than 20 international partners, to form the International Medical Products Anti-Counterfeiting Taskforce (IMPACT). WHO has launched a challenge to technology providers to come up with technologies to detect and track counterfeits.

Many materials are semitransparent in the terahertz region and have “terahertz fingerprints,” allowing them to be imaged, identified, and analyzed. TeraView’s 3-D terahertz pulsed imaging system is designed to examine the core and coatings of tablets, providing nondestructive direct analysis. The system contains a Ti:sapphire ultrafast laser and a laser-gated photoconductive semiconductor emitter; the detector is also laser gated. Radiation is generated in the spectral range of 40 GHz to 4 THz.

Terahertz imaging can produce a 3‑D “fingerprint” of a tablet, which is compared with a database of such fingerprints from known manufacturers. The structure of tablet coatings and cores tends to be different between different manufacturers.

“Every tablet has a fingerprint that is unique to the coating, the contents, and potentially the manufacturer, which we can detect with our terahertz imaging technology,” says Don Arnone, chief executive officer of TeraView. “We can not only determine whether the drug content is as described, checking for active constituents, for example, but also differentiate brand-name drugs from other manufacturers.”