How does inhaled insulin work

by: Anita Cherry
There has been lots of research in the field of insulin administration. To keep blood sugar under control insulin is injected. Patients would prefer inhaled insulin to injected insulin especially, when sometimes you have to take up to 6 injections daily. The different targets tried for insulin delivery are through the upper airways i.e. the mouth, the nose , the skin and even as suppositories. Oral delivery is not possible due to the acidity of the stomach and the digestive enzymes of the intestines which prevent the insulin molecules to absorb into the blood. Inhaled insulin can reduce or eliminate the daily insulin injections.There are several systems in developmental phase by different pharmaceutical firms with products like AerodoseR , AERxTM Diabetes Management System, QdoseR and ExuberaR . An advisory panel to the U.S. Food and Drug Administration on September 8th 2005 recommended approval of Exubera an inhaled insulin for adults with type 1 or type 2 diabetes. It is predicted that Pfizer would launch Exubera in late 2006.Exubera is produced by Sanofi-Aventis and Nektar Therapeutics, a California biotechnology firm (formerly Inhale Therapeutic Systems, Inc.) in partnership with Pfizer.Other inhalable insulins still on human testing are by Indianapolis-based Lilly and Alkermes Inc., and another is by the Danish firm Novo Nordisk and Aradigm. The Lilly-Alkermes inhaler is small enough to fit in the palm of the hand and is breath-activated, but Exubera, a larger device and it relies on compressed air to operate. The Lilly-Alkermes inhaler is expected to reach the market only by 2008.How does inhaled insulin work?The delivery of the Exubera is designed in such a way that this should be small enough to get into the lungs and not large enough to be breathed out. Exubera is a rapid-acting, fine dry-powder insulin. The blister packs are loaded into the inhaler device and a trigger is squeezed to disperse the insulin powder into the compartment above. When this is inhaled through the mouth the finely powdered air reaches directly into the lungs. Insulin passes through the alveolar wall found in the lung and enters into the blood circulation. Breathing once or twice would be sufficient. The content in the blister pack is 20 % insulin and 80% is not revealed. The insulin is reported to be stable for 6 to 24 months at room temperature. Proper training will also be given to people on how to use the inhaler properly. Inhaled insulin enters the bloodstream more rapidly than by subcutaneous injection. Blood sugar control was equivalent when compared to injected regular and inhaled regular insulin. There are some concerns about the long term effects of chronic inhalation of a growth protein into the lungs. Some experts are also worried about people exposed to second hand smoke or lung disease like asthma or emphysema especially since there have been minor reductions in breathing efficiency in some patients and some patients reported coughing.This inhaler is also effective during cold and upper respiratory infections but may not be that effective during pneumonia. Smokers will be excluded from taking the drug because the cells in the lungs will be already damaged due to smoking their blood sugar could fall dangerously low with Exubera because they absorb much more inhaled insulin in their lungs than nonsmokers.Delaying insulin treatment can contribute to higher blood sugar levels, which can lead to complications such as nerve damage, cardiovascular problems, vision loss and kidney disease.