Close Menu
Microneedle Patches: A Transdermal Innovation

Transdermal Innovation: Why We Need Microneedle Patches to be an Industry Disruptor

Late last month, the World Health Organization published surveillance data that revealed the high level of antibiotic resistance to a number of serious bacterial infections.  The data revealed widespread occurrence of resistance across 22 countries.

“Some of the world’s most common — and potentially most dangerous — infections are proving drug resistant,” said Dr. Marc Sprenger, director of WHO’s Antimicrobial Resistance Secretariat.

The surveillance systems have been monitoring tuberculosis, HIV, malaria and cancer.

So how can the converting industry fit in to this alarming trend?  For the answer, we reached across the sea to Belfast, Ireland, to Dr. Ryan Donnelly, and the fascinating innovation called microneedle patches.

Dr. Ryan Donnelly

Dr. Ryan Donnelly

Why is antibiotic resistance snowballing out of control?   

Before we dive into Dr. Donnelly’s work, let’s understand the root cause of the increasing global resistance to antibiotics.  

Antibiotics are typically administered orally, and they’re only administered when you’re sick.  When you take the antibiotic orally, it is exposed to gut bacteria. “This is an ideal situation for resistance to develop,” Dr. Donnelly explained.  

As the bacteria develops a resistance, the antibiotics become less effective. Compounding the problem is that pharmaceutical companies  — which are relied upon to create the next generation of antibiotic drugs — are resistant to act. Why? Because, sad to say, it’s not a good business move.

When a patient needs antibiotics, it’s usually for an infection.  A dosage is prescribed for a 1-2 week period. That’s not a steady stream of income for pharmaceutical companies. It’s much more lucrative to produce drugs for chronic problems like blood pressure and diabetes.

We have growing resistance to antibiotics.

As a result, not only do we have a growing resistance to antibiotics, but the traditional mechanism for fixing the problem is not responding.  Enter Dr. Donnelly.

Where they are now is not where they started

Like most innovations, Dr. Donnelly’s work began with an entirely different focus.  In 2004, he was developing photosensitizer delivery systems for non-melanoma skin cancer.

The overall market for that type of solution is small, however. Dr. Donnelly decided to switch his focus to the mode of distribution. “We changed our mind to focus on drug delivery in its broadest sense,” Dr. Donnelly said.

He had been working on photosensitizing compounds, which are delivered through the skin. Epidermal absorption allows patients to avoid the oral delivery system (with the gut bacteria issues), and the use of needles or syringes (which can include issues regarding infection and waste disposal).

It seemed like the ideal delivery method for vaccines and antibiotics, but the problem was the mechanism. How could photosensitized compounds be administered in a safe, easy-to-use manner that was also cost-effective?

The sticking point: Needles

Dr. Donnelly had been researching the delivery of photosensitizing compounds through microneedles. Microneedles are a cluster of small needles, less than 1 mm in size.  Arranged on a patch, the tiny projections can painlessly penetrate the outer layer of the skin.

Microneedles Hydrogel Formulation

Microneedles can be used to deliver medication or to monitor the level of drugs in the patient’s body without drawing blood. The sticking point for Dr. Donnelly’s team (please excuse the pun) were the needles.

Initially, silicon needles were considered. These were a micro-version of the traditional needle and syringe.  However, silicon needles would need to be coated prior to use, and there was still the risk for infection and disposal problem.

Dr. Donnelly needed an alternative to silicon needles. He found it by accident.

Serendipitous solution: Hydrogels

The group had been focusing on making flexible topical patches.  To make them flex, they needed a plasticizing agent. They began to use hydrogels.  To their surprise, this softening agent was cross-linking. It would become hard and swell when used.  

If the needles were constructed out of the hydrogels, they could swell, adhere to skin, yet give Dr. Donnelly’s team the ability to control the dosage.  

Even better, disposal was simple.  “The hyrodgel doesn’t deposit any of the plastic materials in the skin,” he said.  “It’s removed intact but soft. You can’t stick it to another person.” The patch can then simply be thrown away, like a used band-aid.

More a case of buying time than a solution

Dr. Donnelly’s work has earned him a grant from The Wellcome Trust, with the goal of showing microneedles can deliver antibiotics effectively.  “We are confident we can do it — we’re already delivering high doses,” he said.

Professor Ryan Donnelly

The goal is to extend the useful lifetime of existing antibiotics. As Dr. Donnelly explains, “We bypass the gut bacteria and the antibiotics are excreted by the kidneys, so resistance in the gut bacteria does not develop and the useful lifetime of existing antibiotics is extended.”

He notes the first penicillins, which had to be injected intravenously due to poor oral absorption, took 40 years to develop resistance, because they were avoiding the gut bacteria. Today, administering antibiotics intravenously antibiotics is not an alternative, as this would bankrupt healthcare providers very quickly. Thus the microneedle at-home solution.

The short-term and long-term future for microneedles

Microneedles won’t solve the underlying problem of how the world will develop the next generation of antibiotics.

There is no incentive for pharmaceutical companies to develop new antibiotics, other than the fact that there won’t be anyone around to use their more lucrative drugs if they don’t. “Healthcare providers won’t be able to perform operations and treat cancer patients without antibiotic drugs,” he said.  “You’ll have more people sick, and less people working.”

Dr. Donnelly believes that creating a working economic model will require some sort of agreement between pharmaceuticals and governments. In the meantime, Dr. Donnelly and his team will be focusing on providing a product that delivers on its promise.  

As they make progress, he’s hoping that a pharmaceutical company will jump onboard and add more resources to the process.  

How long until we get microneedles?

If the clinical trials provide successful, patients could benefit from the system “in about five years.” 

As for transdermal patch manufacturing, Dr. Donnelly estimates the patches could produce around $1 to manufacture, although there are many variables at play, including the cost of the antibiotic.  “They may be a lot more expensive than antibiotics in capsule form, but if you can offset the existing lifetime of antibiotics, then you have something worth providing,” he said. 

Considering the impact it could have on global health, we couldn’t agree more.