Skin patches made of thousands of tiny needles could deliver antibiotics directly to the bloodstream, in the process avoiding a major path for resistance to appear and spread. As with almost any method of controlling bacterial disease, this is unlikely to prove a permanent solution, but it could delay the day when long vanquished diseases become untreatable, and buy us the time to come up with other answers.
As more and more bacteria become less vulnerable to the drugs that have saved so many lives, conventional solutions either involve producing new antibiotics faster than resistance can evolve, or using the ones we have more sparingly. Professor Ryan Donnelly of the University of Belfast has an alternative, noting resistance often arises in the gut, as oral antibiotics interact with bacteria there on the way to the blood.
Injecting drugs straight into the bloodstream cuts out this path to the development of resistance, but as Donnelley noted in a statement: “It is clearly impractical to expect patients to inject themselves at home, especially considering that more than 20% of people are needle-phobic. Admitting patients to hospital every time they need an antibiotic would quickly bankrupt healthcare providers.”
What is needed is a way to administer medications to the blood that can be done by unskilled labor, and microneedle patches offer a possible solution. These are arrays of tiny needles, sitting on something that looks like a band-aid, with each needle so small there is almost no pain when they pierce the skin. The needles are made of a substance that, upon entering the skin, turns to a jelly-like consistency that allows antibiotics to follow. Each microneedle carries a tiny amount of medication, but an entire patch is the equivalent of a dose with a hypodermic syringe.
Microneedle patches are already creating considerable excitement for their potential to deliver vaccines in places that lack trained medical staff, and because they don't need refrigeration the way traditional vaccines do. There is also hope their less invasive nature will mollify the fears of anti-vaxxers.
Donnelly has previously published work in the International Journal of Pharmaceutics that showed people can self-administer placebo-carrying versions of these patches with ease. He has now secured funding to conduct experiments using antibiotics, which, if successful, could lead to antibiotic microneedles being on the market in five years time.
Last year Emory University announced the success of a phase I clinical trial delivering the flu vaccine through microneedle patches. It is hoped this will address the shockingly low rate of take-up of influenza prevention, even among medical professionals, but Donnelly may have found an even more important application.
