Up to 30 percent of the medications in the developing world are poor in quality because either they are improperly manufactured, degraded because of age or poor storage, or produced as counterfeits in rogue factories. The bad medicines can cause severe side effects and death. Identifying them is challenging, however. Many countries lack regulations or routine inspections. Testing equipment can be scarce, cumbersome and costly and can require extensive training—and provide only partial information about a drug's ingredients.
A new device from Boston University, called PharmaCheck, may offer a portable, inexpensive and informative solution. The toolbox-size unit reveals the concentration of active ingredients, as well as how fast they are released. This “dissolution rate” sets PharmaCheck apart from other technologies, says Muhammad Zaman, a biomedical engineer who leads the work; active ingredients that break down too quickly can cause a life-threatening overdose.
To use PharmaCheck, an individual dissolves a pill in a few deciliters of water, then adds a second solution, included in the kit, called a fluorescent probe, which is tailored to bind to the active ingredient in a particular drug or class of drugs. The probe and dissolved drug interact in tiny channels etched into a silicon-polymer testing chip. The probe fluoresces, emitting light that is read by a sensor. Software translates the reading into an estimate of the ingredient's concentration, according to calculations made by Zaman's laboratory. Monitoring the signal over time indicates the ingredient's dissolution. Within minutes a doctor, regulatory official or health worker can have a definitive answer as to whether or not a pill is safe.
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This winter Zaman will test prototypes in Ghana and Indonesia, with help from Promoting the Quality of Medicines, an international aid program. So far the team has crafted three probes for antimalarial and antibiotic drugs—among the most common substandard medications in circulation. They will add probes for uterotonic drugs (which induce labor) and antituberculosis and anti-HIV medications. Researchers must design a probe for each active ingredient, and PharmaCheck can test only one at a time. It cannot directly detect unwanted ingredients, such as cheap filler materials; however, because impurities generally alter the way in which an active ingredient breaks down, the portable lab could flag their presence.
PharmaCheck is one example of the great progress made in microfluidics: technologies that manipulate liquids within channels much less than a millimeter wide. “This could not have happened 10 years ago,” Zaman says. In the future, so-called labs-on-a-chip could test dietary supplements or veterinary medicines or rapidly screen blood and saliva samples.
Researchers elsewhere are developing other approaches to identifying substandard medicines. Chemists at St. Mary's College and the University of Notre Dame, for example, have created a paper card that users can dampen and rub a crushed pill across, which generates a colorful array to confirm a pill's contents.
If these kinds of tests were available to small pharmaceutical companies, pharmacies, hospitals, health workers and government regulators, quality could be assessed at every stage of the drug pipeline. That rigor could also help stem the influx of poorly made generic drugs into the developed world, as well as counterfeits sold online for blockbusters such as Viagra.
