Formulation and evaluation of insulin dry powder for pulmonary delivery

Oral delivery is the most convenient and the most acceptable route. However, insulin by itself is degraded by intestinal enzymes and is not absorbed intact across the gastrointestinal mucosa. Now, a day gelatin, trypsin coated capsule, pill, pellets may be available. It has some disadvantages; a lot of the insulin will be wasted before it gets where it's going. Insulin taken as a pill is quickly broken down in the stomach, just like the food you eat. That makes it useless for lowering blood glucose levels. Intensified insulin therapy consists of basal insulin given in the form of either twice-daily injections of delayed action - lente or isoplane (NPH) insulin or once- or twice- daily injections of longer acting ultralente Continuous subcutaneous Insulin infusion (CSII) from a portal pump is used for basal insulin. Prandial insulin is given by injection of short-acting insulin given 30 min before meal. E.g. Insulin syringe, pen, an insulin pump. The pulmonary route of administration offers several advantages. First, the lung has a large surface area for drug absorption, ranging from 100 to 140 m2. In addition, the alveolar epithelium has permeability that allows for rapid absorption of solutes. Because the mucociliary clearance of the alveolar lung tissue is slower than that of the bronchiolar tissues, the alveoli provide a greater opportunity for the absorption of larger molecules (e.g., insulin).