A new long-term contraception has been designed for women to self-administer using a microneedle patch.
Providing a new family planning option, particularly in developing nations where access to healthcare can be limited, this new long-term contraception would be delivered using microneedle patch technology originally developed for the painless administration of vaccines.
Long-acting contraceptives that are currently available provide the highest level of effectiveness, but usually require a healthcare professional to inject a drug or implant a device. Short-acting techniques, on the other hand, require frequent appliance by users and therefore are often not as effective.
In animal testing, an experimental contraceptive microneedle patch provided a therapeutic level of contraceptive hormone for more than a month with a single application to the skin.
When the patch is applied for a few seconds, the microscopic needles break off and remains under the surface of the skin, where biodegradable polymers slowly release the contraceptive drug, levonorgestrel, over time.
Professor Mark Prausnitz, Georgia Institute of Technology, USA, and the paper’s corresponding author explains: “There is a lot of interest in providing more options for long-acting contraceptives.”
“Our goal is for women to be able to self-administer long-acting contraceptives with the microneedle patch that would be applied to the skin for five seconds just once a month.”
The microneedle patch
If the microneedle contraceptive patch is ultimately approved for use, it could become the first self-administered, long-term contraception that does not involve a conventional needle injection. Like other long-acting contraceptive techniques, the microneedle contraceptive patch would interrupt the menstrual cycles of women using it.
Because the tiny needles must remain in the skin for the time-release of the hormone, researchers developed a mechanical technique that would allow the drug-containing microneedles to break free from the patch’s backing material.
To accomplish that, the researchers shaped tiny air bubbles into the top of the microneedles, creating a structural weakness. The resulting microneedles are robust enough to be pressed into the skin, but when the patch is then shifted to one side, the shear force breaks off the tiny structures in the skin. The patch backing can then be discarded.
Yet to be tested
“We do not yet know how the contraceptive microneedle patches would work in humans,” Prausnitz said.
“Because we are using a well-established contraceptive hormone, we are optimistic that the patch will be an effective contraceptive. We also expect that possible skin irritation at the site of patch application will be minimal, but these expectations need to be verified in clinical trials.
“There is a lot of interest in minimizing the number of healthcare interventions that are needed.
“Therefore, a contraceptive patch lasting more than one month is desirable, particularly in countries where women have limited access to healthcare. But because microneedles are, by definition small, there are limits to how much drug can be incorporated into a microneedle patch.”
Even through the mass-production costs have not been determined, Prausnitz expects the contraceptive patches will be inexpensive enough to use in developing countries.