Review of current insulin and proposal of an advanced nanotechnology inhaled protaphane-polystyrene as alternative

Abstract

Objective: Find out the characteristic of an inhaled insulin as a substitute to injectable insulin.                   Methods: Gather the pitfall of current inhaled insulin and suggest solution based on current nano-technology and commonly used insulin.                   Findings: Currently available inhaled insulin is expensive and can cause hypoglycemia, bronchospasm, and other adverse effects in subjects with pre-existing respiratory diseases as shown in lung function tests. The particle diameter is 1-5 microns. Bioavailability is fair and the inhaled insulin dose is  3-10 times higher than injectable insulin one since only 10% is absorbed through the alveoli to enter the bloodstream. Insulin induces cell division wherever it is deposited which may lead to aberrant cell growth. Current subcutaneous insulin therapy regime is based on the normal human physiology. Either metformin plus 2 doses of intermediate-acting insulin daily or 3 doses of short-acting insulin plus one dose of long-acting insulin daily. Nanoparticle passes directly through epithelium to enter the bloodstream. There is less respiratory tract irritation and the bioavailability is good.Nanoparticle corona (<100 nm) allows hypothetical inhaled protaphane to pass through the lung fluids and its action can be slowed down by polystyrene polymerization.  Nanoporous membranes or adding specific nanoreceptors to drug surfaces are other alternatives.Conclusion: Pure inhaled insulin lowers blood glucose quickly and, being a growth factor, potentially increases aberrant cell growth. Neutral protamine Hagedorn (NPH) insulin is a stable and intermediate-acting insulin. Nanotechnology allows the protaphane nanoparticle to pass through respiratory epithelium and to enter the blood vessels with minimal interaction with pneumocytes.