When women are able to decide for themselves when and if they want children, according to the World Health Organization, everyone wins. Women live healthier lives, infant mortality rates drop, and economies grow as a large section of the population is able to pursue additional education and employment opportunities.
Among the many contraceptives that are available to women, one of the least intrusive methods is a daily contraceptive pill. But these pills must be taken at the same time every day, and a survey conducted in eight countries revealed that between 39 and 65 percent of women missed at least one dose in a three-month period.
Ambika Bajpayee, an assistant professor of bioengineering at Northeastern, has been working with Giovani Travero and Robert Langer at the Massachusetts Institute of Technology to design a contraceptive pill that would need to be taken just once per month.
Their drug delivery system, described in a recent study in Science Translational Medicine, remains in the stomach for weeks, slowly releasing contraceptives.
“You need something that can stay inside the stomach for several weeks, but is strong enough that it can withstand the peristaltic wave forces that break down food,” Bajpayee says. “And not degrade in the acidic gastric environment.”
Their solution resembles a six-armed star, more than two inches across, that is folded into a pill capsule. The arms are loaded with contraceptives mixed with various polymers to slow down their release rate.
Once the pill is swallowed, the capsule dissolves and the star unfolds like a flower blooming in the stomach. Its arms are too wide to fit through to the small intestine.
“Because of its expandable size, it cannot pass through the stomach,” Bajpayee says. “This results in long residence times of three to four weeks, during which contraceptive drugs loaded into the arms of the star are released into the stomach.”
The star eventually breaks down into small pieces, Bajpayee says. The researchers designed specific areas of the star to dissolve, which allows it to pass easily through the digestive system and out of the body.
The group tested their device in pigs, which have digestive systems that exert forces similar to our own. They tried two different formulations of contraceptives. While the researchers say the formulations still need to be refined, the devices worked as intended. Even when mechanical and chemical digestive forces began to break down the structures—several arms were lost—the majority of each device remained in the stomach for the full experiment.
“The mechanical design is such that the device can be retained inside the stomach for a period of 21 to 28 days,” Bajpayee says. “That gives you a proof of concept that it can be loaded with any type of drug and can be used for a long sustained release.”
Langer has launched a startup company, Lyndra Therapeutics, to continue to develop and commercialize the technology. Loaded with different drugs, the star-shaped delivery system could help other patients whose well-being depends on daily pills, like individuals with HIV or various mental health disorders, as well as those looking for an oral contraceptive that doesn’t have to be taken every day.