Star-shaped capsule makes for monthly birth control pill
The Pill is still one of the most common forms of contraception, but it only works if you remember to take it every single day. To remove some of that risk and hassle, researchers at MIT have updated their slow-release, star-shaped oral capsules to last up to four weeks, and used it to deliver contraceptive drugs.
MIT first revealed its star-shaped drug delivery system back in 2016. While it looks decidedly unpleasant to swallow, the star’s arms are designed to fold up to fit inside a regular gelatine capsule, only unfolding once it reaches the stomach.
Once there, the wider star shape lodges in the stomach and gets to work. Each of the six arms are made of polymers and loaded with whatever drug payload is required. As they slowly dissolve over weeks, they release the drug continuously.
When it’s all done, the star’s core – which is made of a biodegradable elastic material – will have dissolved as well. That allows the now-empty polymer arms to break off and move through the gut, where they can be harmlessly expelled in the usual way.
In the past, the team – including scientists from MIT, Brigham and Women’s Hospital, and a spin-off start-up called Lyndra Therapeutics – has used the star design to release drugs for HIV and Alzheimer’s. The HIV test was done on pigs, while the Alzheimer’s version marked the first human clinical trials. In both cases though, the drugs were only released for two weeks.
In the new study, the researchers extended that time frame, and applied the technology to another long-term drug – oral contraceptives. First, the team tested materials for the arms and core that could last longer in simulated stomach acid, and settled on two types of polyurethane.
Then, they tweaked the concentrations of drugs and polymers in the arms, to find the best balance in the rate of release of the drugs. In this case that drug was levonorgestrel, which is often used in contraceptive implants or mixed with other drugs in pills.
When they tested the star capsules on pigs, the team found that the drugs were released fairly constantly for up to four weeks. The concentration of the drug in their bloodstream was similar to what would be expected of someone taking oral pills every day.
“We are hopeful that this work – the first example ever of a month-long pill or capsule to our knowledge – will someday lead to potentially new modalities and options for women’s health as well as other indications,” says Robert Langer, corresponding author of the study.
The team says they hope to begin human clinical trials of the new contraceptive drug delivery system within the next three to five years.
The research was published in the journal Science Translational Medicine.