Low-Cost Tool Reveals Fake Drugs by Dissolution Patterns

Counterfeit medications threaten global health, with the World Health Organization estimating that 1 in 10 drugs—from cancer treatments to contraceptives—are fake or substandard. These fakes primarily burden developing countries but also infiltrate U.S. markets for weight-loss and anti-aging products. “Watered-down or illicit versions of drugs like Botox or popular GLP-1 inhibitors have caused serious injuries or death,” said William Grover from the University of California, Riverside.

Grover’s laboratory recently developed a low-cost tool, buildable for under $30 or potentially $5, with details published in Analytical Chemistry. It repurposes an infrared sensor from toy robots—designed for line-following—to monitor pill dissolution rates in water. Genuine pills from one manufacturer dissolve consistently, creating a unique “dissolution fingerprint” tied to their production process and ingredients. Fakes, produced elsewhere with different materials, produce mismatched patterns.

“The theory here is that if it’s a legitimate medicine, the manufacturer made every pill identical enough that they’ll all behave roughly the same way when they dissolve,” Grover explained. “So if you test a suspect pill, and it dissolves at a different rate than the real thing, this suggests the suspect pill is counterfeit.” The tool digitizes this process into a signature for reliable verification.

The team built a fingerprint library by testing over 30 medications, including antibiotics, vitamins, prescription opioids, and over-the-counter painkillers, achieving 90% identification accuracy. It successfully separated name-brand from generic versions too. “We took Bayer aspirin pills and drug-store-brand aspirin—these are basically identical medicines with the same active ingredient and very similar inactive ingredients,” Grover said, “but when ran through our tests, we could easily tell the difference between the two products.”

The team also recruited friends and family who gathered samples across the U.S. and Canada, revealing consistent fingerprints for the same product by region, though some brands adjust formulas for different markets. The approach also catches manufacturing flaws, such as mislabeled ingredients, which can turn honest mistakes deadly.

Looking ahead, Grover targets fake antimalarials, vital in malaria-prone tropics where counterfeits mimic packaging but lack active components. “Unfortunately, bad actors know they can make money preying on the need for antimalarials. They sell pills that have the same packaging as authentic antimalarials, but don’t contain the active ingredients,” he said. “If someone gives these pills to their child, they won’t cure their infection.” Grover seeks broad distribution of the tool to combat such threats.