Insulin patches that attach to the intestinal wall could replace injections for diabetics. Indian- origin scientists are developing a patch which will release insulin after being taken in the form of a pill.
Insulin therapy is an important part of diabetes treatment - used to regulate the level of sugar in the bloodstream and storage of glucose.
Existing marketed insulin formulations are injectables - currently, it is not possible for insulin to be taken by mouth, as digestive enzymes in the gastrointestinal tract break down the protein so that it is no longer active.
Samir Mitragotri, a professor in the College of Engineering at the University of California Santa Barbara, and Amrita Banerjee, a postdoctoral fellow, developed patches made of mucoadhesive polymers loaded with insulin and an intestinal permeation enhancer, then placed the patch devices in enteric-coated capsules.
Once in the intestine, the patch-containing pills are specially designed to dissolve, releasing the patches so that they can attach to the intestinal wall for site-specific delivery of the insulin.
“We’ve created a technology with several innovative features. Our mucoadhesive devices fit inside of a small capsule and then deliver the drug in the intestine in a very effective manner,” said Mitragotri.
“There are many possible benefits and advantages of an oral delivery for insulin,” he said.
The mucoadhesive strength of the patches was determined by placing patches on porcine intestine. After 30 minutes, the patches were gradually pulled away from the intestine and the strength required to completely detach the patches from the intestine was quantified using a microbalance.
To further assess the efficacy of the patches, diabetic rats were fasted overnight and orally fed the capsules. Blood glucose levels were thereafter determined at different time points for up to eight hours using a commercial blood glucose meter to calculate the per cent drop in glucose levels.
The patches showed a complete drug release profile, releasing 100 per cent of the insulin and permeation enhancer content within five hours of study and demonstrated an excellent mucoadhesive strength. In vivo efficacy studies showed that insulin patches containing 10 per cent permeation enhancer were the most effective formulation.
The next stage of the research is to continue in vivo rat studies to evaluate the intestinal patches for faster or extended release of insulin.
The research was presented at the 2015 American Association of Pharmaceutical Scientists (AAPS) Annual Meeting and Exposition in Orlando.