The development of an oral form of insulin has been a work in progress for many years. Many companies have decided to look for an oral form of insulin as this will help patients become more compliant with insulin therapy. They would be easier to carry around and simpler and more discreet than injecting it, so patients would be able to maintain more privacy about their need to take insulin.
Many ideas are in the works from sprays to pills. The difficulty with pills is that insulin gets easily destroyed by digestive juices in the stomach and small intestines. Finding a coating for the pill that would protect it as it traveled and dissolved once it reached the stomach was the initial problem. Also, the amount of insulin that can be put in a pill is small compared to what can be delivered in a syringe.
Insulin delivered by the oral route follows the same route to the bloodstream as insulin secreted naturally by the pancreas into the portal vein. Insulin, from the pancreas or from oral delivery, reaches the liver in high concentrations (3 times more than other tissues), activating the liver to participate in blood sugar control and regulate a number of metabolic activities that can help mitigate complications of diabetes. An oral tablet insulin product would do away with the above-cited limitations of injectable insulin, and inhaled insulin, in addition to the fact that oral delivery would have high patient compliance. Below are some companies currently trying to make this delivery process possible.
Dr. Alessio Fasano of the University of Maryland reported on research that might one day allow insulin pills to work. The report in the March, 1997 Journal of Clinical Investigation (pgs. 1158-1164), uses a protein called Zonula occludens toxin or Zot. With Zot, researchers were able to significantly increase insulin transport across the intestines to lower blood sugar levels to nearly normal levels in diabetic rats. Zot is derived from Vibrio cholera. This basic research has many hurdles to pass before clinical trials begin, but offers an interesting approach to the problem of protein breakdown in the stomach and intestines.
Noven Pharmaceuticals of Miami has developed transoral patches for delivery of anesthetics for dental work, and for treating motion sickness, angina and nicotine withdrawal. They are attempting to use similar technology to transport insulin across the membranes in the mouth. This approach faces several problems in maintaining oral healthy membranes, preventing allergies to the adhesives used, keeping the patch in place, and not having unwanted compounds or viruses also cross the oral membrane alongside the insulin.
Links to other stories
Pumping Insulin provides much more pump information and is the most helpful book ever written on insulin use.
Using Insulin takes you step by step toward excellent control. Whether you use one injection and pills, or six injections, you'll learn far more from this book than from any other!