Microneedle patches already show a great deal of promise as a painless alternative to hypodermic needles. A new one, however, could find use as a more effective means of treating serious bacterial infections of the skin.
In most cases, microneedle patches take the form of a small, flat square of material with an array of tiny, sharp, medication-filled studs – or "microneedles" – on its underside. While the main patch is usually made of a non-toxic polymer, the needles are made of a substance that will harmlessly dissolve once within the body, such as silk.
When the device is pressed against a patient's body, the microneedles penetrate the outer layer of the skin, not reaching any of the nerves beneath. Those needles then dissolve, releasing the medication into the interstitial fluid between the skin cells – from there, it travels into the bloodstream.
Led by Assoc. Prof. Georgios Sotiriou and PhD student Jill Ziesmer, scientists at Sweden's Karolinska Institutet have taken that same basic technology and applied it to the localized treatment of MRSA (methicillin resistant Staphylococcus aureus) skin infections.
Ordinarily, such potentially lethal infections are treated by injecting the antibiotic vancomycin into the patient's bloodstream. The drug isn't usually applied topically, since it doesn't penetrate the skin well, nor is it administered orally, as it isn't absorbed well through the gut. Unfortunately, though, injecting it causes the medication to be carried throughout the body, producing unwanted side effects.
With this drawback in mind, the researchers have developed an experimental microneedle patch that is placed on the skin at the site of an MRSA infection, delivering vancomycin directly into the skin via the needles. Because the medication goes straight to the infection, and is mostly retained there instead of entering the bloodstream, a lower dosage is required than if it were to be injected and dispersed throughout the body. Therefore, side effects should be greatly minimized.
In lab tests conducted on skin samples from piglets and humans, the microneedle patch was shown to be effective at delivering vancomycin into the skin, resulting in a significant reduction of MRSA bacteria. Live animal trials are now being planned, possibly followed by human clinical trials.
"If this drug delivery device reaches the clinics, it has the capacity to transform the way skin infections from potentially lethal bacteria are treated with drastic improvements in the quality of life of patients," says Sotiriou.
A paper on the research was recently published in the journal Advanced Materials Technologies.
Source: Karolinska Institutet
