Magnetic Microspouter Regulates Drug Delivery

A magnetic drug implant based on a silicone sponge can be used to remotely trigger the release of medication into surrounding tissue, according to a new study.

Developed by researchers at the University of British Columbia, the microspouter implantable device (which is just six mm in diameter), is composed of an silicone sponge with a core of carbonyl iron particles wrapped in a round polymer layer; a reservoir for the sponge installation and drug loading; and a soft membrane for sealing the device. The sponge is designed to provide the force necessary for drug release through magnetic field-induced reversible deformation.

The drug of choice is first injected into the device, and then surgically implanted in the treatment area. Following application of a magnetic field to the microspouter, the shrinking sponge triggers a “spouting” of the drug through a microaperture in the membrane. In an ex-vivo experiment on animal tissue with the prostate cancer drug docetaxel, the microspouter was found to have low background drug leakage that could allow for tunable drug release. The study describing the microspouter was published February 10, 2017, in Advanced Functional Materials.

“Actively controlling drug delivery is particularly relevant for conditions like diabetes, where the required dose and timing of insulin varies from patient to patient,” said study co-author research scientist John Jackson, of the UBC faculty of pharmaceutical sciences. “This device lets you release the actual dose that the patient needs when they need it, and it's sufficiently easy to use that patients could administer their own medication one day without having to go to a hospital.”

“All the results confirm the microspouter as a potential device for safe, long-time, and controlled drug release in local disease treatment,” conclude senior author professor of mechanical engineering Mu Chiao, PhD. “This could one day be used for administering painkillers, hormones, chemotherapy drugs, and other treatments for a wide range of health conditions. In the next few years we hope to be able to test it for long-term use and for viability in living models.”

Triggerable devices capable of on-demand, controlled release of therapeutics are attractive options for the treatment of local diseases, because of their potential to enhance therapeutic effectiveness with reduced systemic toxicity, and because they can offer an alternative for patients struggling with numerous pills or intravenous injections.