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Oral Insulin Patch

Oral Insulin Patch for Diabetes Sufferers on the Horizon

For several years, scientists have been experimenting with oral insulin delivery mechanisms, including the use of liposomes, to shield insulin from being destroyed by gastrointestinal (GI) secretions customarily used to break down food particles into items our body can extract energy from. Hence, subcutaneous injections are thus far the only effective delivery system of the hormone to keep blood glucose levels within normal parameters in diabetics. Contributing to the efforts of creating a needleless insulin delivery system, scientists at University of California, Santa Barbara have developed an oral insulin patch made from mucoadhesive polymers, to help stick to the intestinal wall lining, in addition to being treated with an intestinal permeation enhancer, for better absorption and exposure to the bloodstream, to be encapsulated into a pill with an enteric coating to withstand the corrosive environment of the GI tract.

Once swallowed, the patch is designed to be released from the pill at a designated time and expected to attach to the intestinal wall for superior insulin delivery into the bloodstream. When patch adhesiveness was tested after 30 minutes upon being attached, stickiness was found to be “excellent” based on the force required to pull off the patch. Release of drug was tested on pig and rat intestines, in which 100 percent of the insulin and permeation enhancer was disseminated within five hours.

In animal studies, the scientists found insulin patches with 10 percent permeation enhancers to be the most effective than control groups, dropping blood glucose levels to 70 percent of normal levels.

Studies are ongoing to discover ways to deliver insulin faster as well as prolong the effects of the patch. For diabetic sufferers who cannot rely on oral medications to control their blood sugar levels, an oral insulin patch may be just the ticket to forgoing the daily prick.

Oral Insulin May Be a Future Option for Diabetics

For type 1 diabetics and some type 2 diabetics, insulin injections are a daily requirement to maintain healthy blood glucose levels. Due to fear of needles, adherence to the regimen may be lacking in some diabetics. Indian scientists at the National Institute of Pharmaceutical Education and Research in Punjab may have found a way to manufacture oral insulin as a replacement for its injectable counterpart.

The main barrier to successfully synthesizing oral insulin is that it is degraded in the gastrointestinal tract (GIT) by digestive enzymes before it reaches the bloodstream. Even if the insulin managed to bypass the enzymes, the intestines do not readily absorb the hormone to enter the bloodstream, where it can aid sugar intake by cells to be used as fuel.

To keep orally delivered insulin intact, the scientists loaded the hormone into a liposome—an artificial vesicle (bubble encasing) made of lipids, or fats—which is a known substance in the pharmaceutical industry and thus readily made. The liposome-insulin package is then layered with polyelectrolytes, to form what the researchers call “layersomes,” to protect the bundle from lipid-degrading enzymes in the GIT. Lastly, a folic acid ligand was attached to the layersomes to aid with liposome absorption in the GIT.

When oral insulin in the form of layersomes was fed to rats, the scientists found it was just as effective as insulin injections in lowering blood glucose levels, and that it even lasted longer. With the oral form, the researchers are hoping it can also combat the side effects of insulin injection administered subcutaneously, such as transient hypoglycemia, peripheral hyperinsulinemia, and weight gain, while improving compliance to medication regimen.

More research still needs to be done on layersomes and polyelectrolyte technology to fine-tune them for mass production and public consumption. Nevertheless, oral insulin no longer appears to be a pipedream.