Designer Delivery

We’ve all heard of transdermal patches for drug delivery, but what about drug delivery through jewelry? Researchers from the Georgia Institute of Technology have been experimenting with delivering drugs through earrings (1). For now, they have focused on the delivery of contraceptives, but the approach could be adapted to other therapeutics too.

“We have been working on a few different approaches to developing contraceptive delivery systems to make adherence to dosing schedules easier. Many contraceptives, such as daily pills, work extremely well if used correctly, but in typical use have lower efficacy because people forget to take the medicine according to schedule. In addition to facilitating improved adherence, we also seek to make contraceptive use discreet,” explains Mark Prausnitz, Regents Professor and J. Erskine Love Jr. chair in the School of Chemical and Biomolecular Engineering at the Georgia Institute of Technology.

The skin is a formidable barrier and prevents the delivery of most drugs. However, there are a number of successfully commercialized transdermal patches that use drugs which are low molecular weight, lipophilic and low dose. Transdermal patches offer simplicity to the patient because they can be applied to the skin just once per week and left in place to continuously deliver contraceptive hormone. However, they aren’t very discrete and transdermal contraceptives can come with side effects associated with estrogen administration (Ortho Evra has a black box warning in the US).

Prausnitz’s team came up with the idea of “hiding” a transdermal patch in jewelry, such as earrings. “Many women are into the habit of putting on earrings and other jewelry on a daily basis, so associating the patch with jewelry could increase adherence. And by making a progestin-only patch using levonorestrel, we avoid the complications of administering estrogen,” he says. “The biggest challenge was making the patch small enough to fit onto an earring back or to be incorporated discreetly into jewelry. We accomplished this by using an electrospinning method to fabricate the patch.”

There was also the challenge of ensuring the controlled release from the patch was enough to be effective. Contraceptive tablets deliver daily boluses of drug, which result in peaks and valleys in contraceptive levels in the body whereas a transdermal patch maintains a relatively steady contraceptive level in the body, which can have advantages. According to Prausnitz, a steady rate of drug delivery from the team’s patch is achieved by maintaining a relatively constant contraceptive hormone concentration in the patch throughout the delivery process by keeping the solution in contact with the skin saturated with drug from the electrospun fibers that make up the patch matrix.

The patches could potentially be incorporated into other forms of jewelry too, but the researchers chose an earring back because the earring back offers a flat surface that is normally in contact with skin. “It is straightforward to adhere a small patch to the earring back and thereby sandwich the patch between the earring back and the skin,” says Prausntiz. “Although the permeability of the skin on the earlobe is not the same as other parts of the body, it can still allow for adequate delivery of contraceptive hormone if the patch is designed for that skin site.

The team is currently working to further optimize the patch design and looking to perform additional preclinical studies of pharmacokinetics and safety in animals.