Rice Lab technology could deliver sustained-release drugs, vaccines over months
Missing critical doses of medicines and vaccines could be a thing of the past, thanks to next-level technology from Rice University bioengineers for making sustained-release drugs.
“This is a big problem in treating chronic diseases,” said Kevin McHugh, corresponding author of a study on the technology published online in Advanced Materials. “It’s estimated that 50% of people aren’t taking their meds correctly. With this, they just give him one shot and the next he’s ready for two months.”
The costs can be enormous when patients do not take prescription drugs or take them incorrectly. In the United States alone, he is estimated to have over 100,000 annual deaths, up to 25% of hospitalizations, and more than $100 billion in medical costs.
Encapsulating drugs into microparticles that dissolve and release the drug over time is not a new idea. But McHugh and his graduate student Tyler Graf have used 21st-century methods to develop next-level encapsulation technology that is far more versatile than the prior art.
Called PULSED (Particles Uniformly Liquified and Sealed to Encapsulate Drugs), the technology uses high-resolution 3D printing and soft lithography to create more than 300 non-toxic, biodegradable drugs that are small enough to be injected with a standard hypodermic needle. Generate an array of cylinders.
The cylinder is made of a polymer called PLGA, which is widely used in clinical medicine. McHugh and Graf demonstrated four methods of loading microcylinders with drugs and fine-tuning the PLGA recipe to vary the rate at which the particles dissolve and release drug, from as little as 10 days to almost 5 weeks. has shown that it can be done. They also developed a quick and easy way to seal the cylinder. This is an important step in demonstrating that the technology is scalable and can address major hurdles of sustained drug delivery.
“What we’re trying to overcome is ‘primary release,'” McHugh said, referring to the uneven dosing characteristic of current drug encapsulation methods. “The general pattern is that many drugs are released early on day one, and he may be ten times less on day one than he was on day one.
“If you have a large therapeutic window, even less than 10-fold release on day 10 might be fine, but it’s rarely the case,” McHugh said. “Most of the time, it’s really a problem because the dose on the first day approaches toxicity, or only 10-fold less, or 4-fold or 5-fold less at later time points. because it is not enough to
In many cases, it is ideal for patients to keep the same amount of drug in their bodies during treatment. McHugh says PULSED can be tailored for that kind of release profile and can be used in other ways as well.
“Our motivation for this particular project actually came from the vaccine space,” he said. “Immunization often requires multiple doses over many months. It’s hard, the idea was, “What if we make a particle that exhibits pulsatile emission?” We then hypothesized that this core-shell structure, which entraps vaccines in pockets within a biodegradable polymer shell, could generate such all-or-nothing release events and provide a reliable method of setting delayed timing. release. “
PULSED has not yet been tested for delayed release over months, but McHugh said previous studies from other labs have shown that PLGA capsules are formulated to release drug as long as six months after injection. It shows what you can do.
Graf and McHugh showed in their work that particles with diameters ranging from 400 microns to 100 microns can be made and loaded. According to McHugh, this size allows the particles to stay where they are injected until they dissolve, allowing him to administer large or continuous doses of one or more drugs to specific locations, such as cancerous tumors. may be useful for
“For toxic cancer chemotherapy, you would want to focus the poison on the tumor and not on other parts of the body,” he said. I injected it into the tumor, but the question is how long it takes for it to spread.
“Our microparticles stay where you put them,” says McHugh. “The idea is to make chemotherapy more effective and reduce its side effects by focusing the drug precisely where it is needed.”
The important discovery of the non-contact sealing method happened by chance. McHugh said previous work had explored using his PLGA microparticles for sustained-release drug encapsulation, but sealing large numbers of particles proved to be very difficult, so Manufacturing costs were considered impractical for many applications.
While considering alternative sealing methods, Graf realized that trying to seal the microparticles by dipping them in different molten polymers did not produce the desired results. “Ultimately, I wondered if it was necessary to immerse the microparticles in a liquid polymer,” he said, suspending the PLGA microparticles on top of a hot plate so that the top of the particles could melt and the bottom could self-seal. says Graf. “Those first batches of particles were barely sealed, but it was very exciting to see that the process was possible.” realized and ultimately proved to be one of the easier steps in manufacturing: time-release drug capsules. Each array of 22 x 14 cylinders was about the size of a postage stamp, and graphs were made of them on glass microscope slides.
After loading the arrays with drugs, Graf said they briefly hang the arrays about a millimeter above the hotplate. “I flip it over, one on each end, another he puts on two glass slides, and set a timer for how long it takes to seal. It only takes a few seconds.”
Original: 21st Century Remedy for Missed Pills
Than: Rice University
