Managing blood sugar levels requires round-the-clock attention. But many people diagnosed with diabetes also need to take regular shots of insulin -- the primary hormone that regulates sugar. To deliver this drug in a less invasive way, researchers from the University of Lille reported in the journal ACS Applied Bio Materials a prototype insulin-loaded patch that comfortably sticks to the inside of a person's cheek.
People primarily take insulin by injecting themselves with pens or syringes, or they have semi-permanent pumps implanted. These methods are invasive and uncomfortable, and they require safe needle or biohazard disposal and sterile conditions. Researchers have explored other ways to deliver insulin through the skin, such as gel-like lotions.
The membrane lining the inside of the mouth is very thin, about one quarter the thickness of skin, making it a potential place for drugs to easily enter the bloodstream. So, Sabine Szunerits and colleagues from the University of Lille wanted to see if a material they had previously developed -- a polymer fiber mat that is activated by heat to release drugs -- could attach to the cheek's lining and deliver insulin.
The researchers first soaked small squares in a solution with insulin for three hours. Then the team applied the insulin-loaded patches onto cheek linings and corneas from pigs. Heating the material with a near-infrared laser for 10 minutes to 122F activated the material and released insulin several times faster than through skin.
In addition, the researchers placed the patches in vivo inside the cheeks of three insulin-dependent pigs. The cheek linings showed no irritation or visual changes from the laser's heat. As soon as the material was activated, the pigs' blood sugar levels declined. Simultaneously, the animals' plasma insulin levels increased, which the researchers say is proof-of-concept that this preliminary platform is efficient at getting insulin into the bloodstream.
Finally, six human volunteers placed a placebo version of the patch inside their cheeks, saying it didn’t cause irritation and felt comfortable over a two-hour period.
