Tiny Cylinders for Controlled Drug Release

Researchers at Rice University have developed a new type of microparticle for drug delivery, made from a polymer called PLGA that has already been extensively explored as a component in drug delivery systems. However, what makes these new particles different is the method of loading and sealing them, which appears to give them highly tunable release characteristics and may even allow the researchers to create particles that provide multiple doses of a drug, or continuous dosing, over the space of several months. The researchers have called their new particle creation method PULSED (Particles Uniformly Liquified and Sealed to Encapsulate Drugs), and it involves 3D printing and soft lithography to produce arrays of particles that can be loaded with drugs.

While conventional drug treatment is a cornerstone of medicine, it is not without its flaws. Patients frequently forget to take their drugs and it is inconvenient to have to remember to take a pill every day or visit a clinic for multiple rounds of injections. Many people missed their follow-up doses of COVID-19 vaccines, for instance. These issues have prompted researchers to develop time-release drug delivery systems that can take the hard work out of drug treatment.

“This is a huge problem in the treatment of chronic disease,” said Kevin McHugh, a researcher involved in the study. “It’s estimated that 50% of people don’t take their medications correctly. With this, you’d give them one shot, and they’d be all set for the next couple of months.”

The researchers developed a new way to create and seal drug-loaded particles. This involves creating arrays of tiny PLGA cylinders that are small enough to be injected through a standard hypodermic needle and then loading them with a drug before using heat to seal the particles. By changing the PLGA recipe, the researchers can drastically alter the release profile of the encapsulated drug, permitting release from 10 days to as long as five weeks.

The main goal is to avoid all the drug being released too quickly, but rather tune the recipe to allow slow, continuous release. “The thing we’re trying to overcome is ‘first-order release,'” added McHugh. “The common pattern is for a lot of the drug to be released early, on day one. And then on day 10, you might get 10 times less than you got on day one.

While the researchers have managed to achieve drug release over five weeks to date, they are confident that they can further modify the particles to allow them to release drugs for as long as six months. This could be a game changer for patients with complicated drug regimens.

See a video about the technology below.