Thin-film technique for delivering pain medication

For those who suffer chronic pain, frequent pill popping helps ease the discomfort but a new advanced thin-film capable of delivering drugs over a period of months could provide an alternative. Developed by researchers at Massachusetts Institute of Technology (MIT), the biodegradable nanoscale thin-film could provide localised, steady doses and can be directly injected or used to coat implantable medical devices. “It’s been hard to develop something that releases medication for more than a couple of months,” said Paula Hammond, the David H. Koch Professor in Engineering. “Now we’re looking at a way of creating an extremely thin film or coating that’s very dense with a drug, and yet releases at a constant rate for very long time periods.” A paper published in Proceedings of the National Academy of Sciences details the method used in the new drug delivery. “You can potentially implant it and release the drug for more than a year without having to go in and do anything about it,” said Bryan Hsu, a doctoral student in Hammond’s lab. “Normally to get long-term drug release you need a reservoir or device, something that can hold back the drug. And it’s typically non-degradable. It will release slowly, but will either just sit there and you have this foreign object retained in the body, or you have to go recover it.” The team developed a layer-by-layer technique in which diclofenac molecules were attached to layers of thin-film coating – a poly-L-glutamic acid consisting of an amino acid the body reabsorbs, and two other organic compounds. The film can be applied to degradable nanoparticles for injection into local sites or to coat permanent devices such as orthopaedic implants. The diclofenac was released over 14 month, but because the effectiveness of the pain medication is subjective, researchers evaluated the efficacy of the method by analysing how well it blocked cyclooxygenase (COX) activity, finding the method works as well as pills. The method also allows researchers to adjust the quantity of drug being delivered by adding more layers of the ultrathin coating. It can be applied to many other drugs, not just diclofenac, although researchers will have to work out how best to bind the drug molecule in question to the coating.