Novel skin patch that painlessly delivers medicines in cancer in a minute
Researchers at the Massachusetts Institute of Technology (MIT) have developed a fast-acting skin patch that efficiently delivers medication to attack melanoma cells without pain. The device is an advance toward developing a vaccine to treat melanoma and has widespread applications for other vaccines.
The researchers have presented their findings at the American Chemical Society (ACS) Fall 2019 National Meeting and Exposition.
Topical ointments can impart medications to the skin, but they can only penetrate a small distance through it. While syringes are an effective drug delivery mode, they can be painful. Syringes can also be inconvenient for patients, leading to noncompliance.
In the past, for making microneedle (MN) skin patches the researchers coat a surface with molecules of alternating positive and negative charge layer-by-layer. With the usual LbL process, every adjacent layer must be strongly attracted to each other and also to the microneedle but this makes the entire film very 'sticky leading to 90 minutes for a sufficient amount of drug to leave the patch and enter the skin. Now researchers have devised a new pH-responsive polymer with two parts. The first part contains amine groups that are positively charged at the pH at which we make the microneedles, but that becomes neutral at the pH of skin and the second part contains carboxylic acid groups with no charge when the microneedles are made, but which become negatively charged when the patch is applied to the skin, so there is an overall change in charge from positive to negative. With this method after the microneedles pierce the skin and implant the LbL drug film beneath the skin, the drug leaves the patch quickly.
The utility of layer-by-layer (LbL) coated microneedle (MN) skin patches for transdermal drug delivery has been proven a promising approach, with advantages over hypodermal injection due to painless and easy self-administration. However, the long epidermal application time required for drug implantation by existing LbL MN strategies (15 to 90 minutes) can lead to potential medication noncompliance.
"Our patch has a unique chemical coating and mode of action that allows it to be applied and removed from the skin in just a minute while still delivering a therapeutic dose of drugs," says Yanpu He, a graduate student who helped develop the device. "Our patches elicit a robust antibody response in living mice and show promise in eliciting a strong immune response in human skin."
"Our patch technology could be used to deliver vaccines to combat different infectious diseases," Paula T. Hammond says. "But we are excited by the possibility that the patch is another tool in the oncologists' arsenal against cancer, specifically melanoma."