Researchers have developed a skin patch with soluble microneedles that regulates blood sugar level for days.
The medical device is infused with a formula that stimulates the pancreas to manufacture and secrete insulin only when needed and automatically stops the stimulation when blood sugar concentration reaches the normal level. Through this delivery method, it can address a patient's therapeutic needs for several days instead of being used all at once.
Since it largely involves natural insulin production, the patch would only work on Type 2 diabetics who still have some capacity to make the hormone. While the device may have its limitations, it presents a more simple and affordable option than multiple daily injections.
New Diabetes Therapy Provides Long-Lasting Effects
In a study, a team at NIH's National Institute of Biomedical Imaging and Bioengineering report testing the patch on mice to prove its effectiveness. The experiment version measured only half a square inch and features microneedles made by pouring alginate, a gummy substance derived from brown algae, into needle form.
These microneedles are then filled with the formula, which contains exendin-4 and glucose oxidase. When these drug compounds are painlessly injected by the microneedles into the dermis, they react with blood chemistry to signal the start of insulin production.
Exendin-4 has the same genetics as the molecule the intestines secrete when it is filled with food. Although it is less potent than the natural version, the compound was selected for the application, as it offers lasting effects.
An excessive dose of exendin-4 is known to cause nausea, which is why researchers paired the compound with calcium phosphate that keeps it stabilized until another chemical reaction is triggered by the second compound.
Glucose oxidase, together with copper phosphate, create a mild acidity when blood sugar concentration goes beyond the normal level. Such acidity prompts calcium phosphate to discharge exendin-4, which induces the secretion of insulin. Once blood sugar level is normalized, calcium phosphate then stops releasing the compound.
"That's why we call it responsive, or smart, release," says NIBIB Senior Investigator Xiaoyuan Chen in a statement, pointing out that most existing therapies only provide "constant release."
Bigger Insulin Patch To Be Developed For Type 2 Diabetes
The experiment may only involve small animals, but it has proven that just a small portion of the patch can already regulate blood sugar level for one week. To develop a device for type 2 diabetics, testing a modified version has to be done on larger animals.
"We would need to scale up the size of the patch and optimize the length, shape, and morphology of the needles," says Chen, noting that it should also be water resistant to allow daily use.
A similar device that can be used even by Type 1 diabetics has already been developed. Chen hopes to learn from such study to enhance his team's skin patch.
