At this time in the United States, injection and infusion are the only methods available for taking insulin — but with various teams of researchers hard at work, and with noninjection forms of insulin already making their debut in certain countries, this situation may change in the future.
One product that is already available in Ecuador, India, and, on a very limited basis, Canada, is Oral-lyn, a formulation of Regular insulin that is sprayed into the mouth using a device similar to an asthma inhaler. The insulin is then absorbed through the mucous membranes lining the mouth. Oral-lyn begins lowering blood glucose levels in 5 minutes, peaks at 30 minutes, and stops working at 2 hours. Unlike inhaled insulins (such as the now-discontinued Exubera), Oral-lyn does not enter the lungs, both because of the design of the device used to take it, and because users are instructed not to inhale as they spray. Oral-lyn is currently in Phase III trials (trials to definitively assess the drug’s effectiveness) in the United States, Canada, Russia, Ukraine, Bulgaria, Romania, and Poland. It is being developed by Generex Biotechnology Corporation and is intended for use in people with Type 1 or Type 2 diabetes.
Oramed Pharmaceuticals, Inc., a company that creates oral methods for administering drugs typically given by injection, is also developing a noninjectable insulin. Presently in clinical trials to assess safety and effectiveness, this drug is a form of Regular insulin that is delivered in capsules that are swallowed. It will initially be intended for use in people with Type 2 diabetes. The capsules are specially formulated to avoid breakdown while in transit through the stomach. The insulin is absorbed in the intestine and then travels first to the liver.
According to the company, routing insulin to the liver first more closely mimics what normally happens in a person without diabetes than injecting or infusing insulin under the skin. The insulin signals the liver to store glucose and to refrain from releasing stored glucose to the bloodstream. This helps to lower the blood glucose level, relieving some of the burden on the pancreas to produce insulin, and therefore helping to preserve pancreatic function for longer.
Oramed Pharmaceuticals plans for the capsules to be available in select countries within the next few years and anticipates approval in the United States to follow several years later.
A set of researchers funded by the Indian government is also in the process of developing an insulin pill, which is scheduled to be studied in human trials within several months. This pill makes use of nanoparticles (extremely small particles) to deliver insulin to the bloodstream. Additional methods of insulin delivery now in the early stages of development are sublingual insulin, or insulin that is placed and absorbed under the tongue; inhalable insulin that is delivered through the lungs; and insulin suppositories to be absorbed through the lining of the rectum.