By Rebecca Bowers

EXECUTIVE SUMMARY

Researchers are studying microneedle skin patch technology for providing a long-acting contraceptive method that can be self-administered.

  • Delivery of the drug involves hundreds of microneedles, each less than a millimeter in length, attached to a small patch about the size of a coin. The patch is applied briefly to the skin. Shifting the patch to one side causes the microneedles to break off into the skin; the patch backing then can be discarded. The microscopic needles stay under the skin’s surface, where the medication releases slowly over time.
  • Researchers plan to study the use of levonorgestrel as the contraceptive agent in the patch.

Researchers are studying microneedle skin patch technology for providing a long-acting contraceptive that can be self-administered by women. Scientists are working with researchers at the Georgia Institute of Technology and the University of Michigan to develop patches with microneedles that deliver a hormonal contraceptive. The patches under study use technology originally developed to administer vaccines.

In animal testing, researchers found that an experimental contraceptive patch using microneedles provided a contraceptive hormone at a therapeutic level for more than a month after one application to the skin.1

There is great interest in providing more long-acting contraceptive options, notes Mark Prausnitz, PhD, Regents Professor in the School of Chemical and Biomolecular Engineering at the Georgia Institute of Technology.

“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,” said Prausnitz, the study’s corresponding author, in a press statement.

The microneedle patch delivery platform represents an exciting advancement in women’s health, says Gregory Kopf, PhD director of R&D Contraceptive Technology Innovation at FHI 360.

“This self-administered long-acting contraceptive will afford women discreet and convenient control over their fertility, leading to a positive impact on public health by reducing both unwanted and unintended pregnancies,” said Kopf in a press statement.

Technology Holds Promise

Delivery of the drug involves hundreds of microneedles attached to a patch that is roughly the size of a coin. Each needle is about one millimeter in length. The patch is applied briefly to the skin; shifting the patch to one side applies a force that breaks off the microneedles into the skin. The patch backing then can be discarded. The microscopic needles stay under the skin’s surface, where the medication releases slowly over time.

Georgia Tech researchers, led by postdoctoral research scholar Wei Li, developed a technique that allows the microneedles to break off from the backing material. Tiny air bubbles molded into the tops of the microneedles create a weakness in the structure that allows the needles to release easily.

The microneedles are made from biodegradable polymers that are commonly used in resorbable sutures, notes Steven Schwendeman, PhD, Ara Paul Professor and chair of the Department of Pharmaceutical Sciences at the University of Michigan. Schwendeman is a collaborator on the current project.

“We select polymer materials to meet specific design objectives such as microneedle strength, biocompatibility, biodegradation and drug release time, and formulation stability,” said Schwendeman in a press statement. “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 microneedles.”

Time to Test in Human Studies

In developing the contraceptive patch, researchers looked at previous work that involved microneedle patches designed for vaccine administration. The findings from a Phase I clinical trial of influenza vaccine that used dissolving microneedles indicated that the microneedle patches could be used to administer the vaccine safely. The microneedles are so small that they only enter the upper skin layers, and patients do not perceive them as painful, findings suggest.2

Scientists do not know yet how the contraceptive patches using microneedles will work in humans, Prausnitz notes. Since researchers plan to work with the contraceptive hormone levonorgestrel, they believe that the patch will offer effective contraception, says Prausnitz.

“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,” he states.

The contraceptive patches that were tested on animal models contained 100 microneedles, but researchers believe larger patches will be needed to provide an adequate dose of levonorgestrel for humans. The researchers are interested in developing a patch for application once every six months. By creating a six-month patch, the number of healthcare interventions could be minimized, which is useful in countries where people have limited healthcare access. However, the amount of drug that can be incorporated into a microneedle patch is limited, says Prausnitz.

REFERENCES

  1. Li W, Terry RN, Tang J, et al. Rapidly separable microneedle patch for the sustained release of a contraceptive. Nat Biomed Eng 2019; January 2019. doi: 10.1038/s41551-018-0337-4.
  2. Rouphael NG, Paine M, Mosley R, et al; TIV-MNP 2015 Study Group. The safety, immunogenicity, and acceptability of inactivated influenza vaccine delivered by microneedle patch (TIV-MNP 2015): A randomised, partly blinded, placebo-controlled, phase 1 trial. Lancet 2017;390:649-658.