Researchers at Purdue University hope to stop drug counterfeiters in their tracks by adding edible security tags onto tablets (1). Despite efforts to use distinct markings, colorings and shapes to deter counterfeits, fake drug manufacturers are still able to infiltrate the market. The problem with current authentication techniques, according to the recently published paper, is that “they are symmetric” – if counterfeiters have access to the same techniques, they are easily replicated. Edible security tags are an advanced anticounterfeiting solution that provide “asymmetric” on-dose authentication down to the individual tablet.
The approach works by applying the concept of physical unclonable functions (PUFs), which were originally developed for hardware security, to the surface of drug capsules and tablets. Like fingerprints, each PUF is unique. When a LED light is shone on the tablet, the tag produces an unpredictable random pattern. Digital bits can be extracted from an image of the patterns to produce a security key, which can be used to confirm the authenticity of the drug.
A smartphone app, currently under development, will allow patients to take a picture of the pattern developed by the tags and identify if the medicines are genuine or fake.
The Purdue team translated the PUF concept to pharmaceuticals by using silk proteins and fluorescent proteins, which are flexible and can be easily digested. “In our initial trial, we attached the PUFs to the surface of capsules. Their flexibility means that they can be attached to flat or curved surfaces but they can also be integrated into tablets during the manufacturing process,” explained Young Kim, an associate professor at Purdue's Weldon School of Biomedical Engineering.
The tags can also be developed to hold information about dose and expiration. Initially, the tags could only last for two months before degrading but since then the team improved the quality of them. “The security tag proteins will remain in good shape so long as they are stored in robust packaging,” Kim explained. Jung Woo Leem, another researcher on the team said, “Our current goal is to ensure that the protein tag lasts as long as the medicine does – and that they don’t affect the quality of key ingredients.”
- JW Leem et al., “Edible unclonable functions”. 2020. Available at: go.nature.com/31Ae2hh
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