Extended-release drug formulations are valuable because they involve fewer pills, less side effects and a steady amount of medication for patients …but health experts say a common problem with these drugs is that they don’t stay in the intestine long enough for people to receive the full dose.
Recently, scientists at Johns Hopkins University cooperated to address that problem. They designed and tested a completely new type of medicine delivery system inspired by a parasite.
Similar to a hookworm – a parasitic worm that digs its sharp teeth into its host’s intestines to feed – Johns Hopkins bioengineers designed tiny, star-shaped microdevices they named “theragrippers,” each about the size of a dust speck, that can latch onto a patient’s intestinal wall and release drugs into the body.
Made of metal and thin, shape-changing film and coated in a heat-sensitive paraffin wax, thousands of theragrippers can potentially be administered at once. When the paraffin wax coating on the grippers reaches the internal body temperature, the tiny devices close and clamp onto the colon wall, gradually releasing the medicine they contain. They eventually lose their hold on the tissue and are cleared from the intestine by normal GI muscular contractions.
David Gracias, Ph.D., a professor in the Johns Hopkins University Whiting School of Engineering, said the devices don’t rely on electricity, wireless signals or external controls. “Instead, they operate like small, compressed springs with a temperature-triggered coating that releases the stored energy autonomously at body temperature,” he explained.
In animal tests, the scientists found that the theragrippers administered higher concentrations of a pain reliever than in a control group that received the same medication orally. The medication also stayed in the animals’ systems for nearly 12 hours, compared to two hours in the controls.