Innovative skin patch may offer long-term contraception

woman looking out the window

Ana Sandoiu 
checked by Carolyn Robertson
Researchers have devised a new
technology that may soon enable women to “self-administer long-acting
contraceptives” in a matter of seconds.

More than 60 percent of women
of reproductive age in the United States are using contraception, according to
the latest estimates from the Centers for Disease Control and Prevention (CDC).
The most popular contraceptive
methods are the pill, with 28 percent of women using it, and female
sterilization, with 27 percent.
The birth control pill is
effective in the short term, but more and more women are opting for long-acting
methods, such as intrauterine devices and implants.
Currently, such long-acting
means of contraception require a healthcare professional to administer them,
but new research may bring the benefits of long-acting contraception in a much
more accessible form.
Researchers led by Wei Li, a
postdoctoral researcher at the Georgia Institute of Technology in Atlanta,
devised an innovative technology that would deliver the contraceptive
levonorgestrel through a microneedle skin patch.
Mark Prausnitz, a Regents’
Professor in the School of Chemical and Biomolecular Engineering at Georgia
Tech, is the corresponding author of the paper, which they have published in
the journal Nature Biomedical Engineering.
the patch and how it works
For their contraceptive
method, Li and colleagues used microneedle skin patch technology, which
scientists have already developed for administering vaccines.
The patch has drug-containing
microscopic needles that break off after a person applies the patch for a few
seconds. The tiny needles then remain just under the skin, releasing the drug.
Li and colleagues molded
microscopic air bubbles into the top of the needles to enable them to break.
The microneedles, after this modification, are strong enough for an individual
to push under the skin but remain weak enough to break when they shift the
patch to one side.
After the tiny needles are
under the skin, they release the hormone levonorgestrel, which disrupts women’s
cycles. The fact that the needles consist of biodegradable polymers helps the
release of the hormone.
Specifically, Li and
colleagues designed the tiny needles from a mix of biodegradable polymers, such
as polylactic-co-glycolic acid and polylactic acid. These acids naturally occur
in the body, explain the researchers, and doctors routinely use the polymers in
absorbable surgical sutures.
Study co-author Steven
Schwendeman, the Ara Paul Professor, and chair of the Department of
Pharmaceutical Sciences at the University of Michigan in Ann Arbor, explains
the polymer selection process.
“We select polymer
materials to meet specific design objectives, such as microneedle strength,
biocompatibility, biodegradation and drug release time, and formulation
stability,” he says.
“Our team then processes
the polymer into microneedles by dissolving the polymer and drug in an organic
solvent, molding the shape, and then drying off the solvent to create the
“The polymer matrix, when
formed in this way, can slowly and safely release contraceptive hormone for
weeks or months when placed in the body,” concludes Prof. Schwendeman.
the patch once a month
The researchers successfully
tested the patch in rats, meaning that the concentration of levonorgestrel they
delivered to the rodents via the skin patch stayed above the threshold that
they knew had a contraceptive effect in humans.
However, scientists are aware
of the challenges that translating these findings into humans pose.
“We do not yet know how
the contraceptive microneedle patches would work in humans,” Prof.
Prausnitz says. “[B]ecause microneedles are, by definition, small, there
are limits to how much drug can be incorporated into a microneedle patch.”
However, the researcher adds,
patches that could deliver the recommended dose of the drug are already
available, although scientists have yet to test them.
“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 providing more options for long-acting contraceptives,”
continues Prof. Prausnitz.
“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 5 seconds just once a month.”

Prof. Mark Prausnitz

Kayode Ojo
Kayode Emmanuel Ojo is the Co-Founder and Managing Director at SHEFFA Limited. He is presently studying Computer Science at the National Open University, Victoria Island, Lagos.