Delivery and retention of an insulin aerosol produced by a new jet nebulizer

This study describes the delivery and distribution of an aerosol generated by a jet nebulizer (MAXIN) in an experimental animal model. Anesthetised, intubated and ventilated piglets inhaled radiolabeled technetium diethylene-triamine-penta-acetic acid (99mTc-DTPA) through the endotracheal tube. The lungs were excised en bloc and scintigraphed, using a computerized gamma camera to evaluate the pattern of distribution. By nebulizing radiolabeled 125I-insulin and comparing the activity deposited on inspiratory and expiratory electrostatic filters, delivery and retention of nebulized insulin was assessed. The distribution of aerosol in the lungs was very even and reached the most peripheral parts. The delivery of nebulized insulin was calculated to be 88.9 +/- 5.3% and 36.1 +/- 8.8% of the insulin delivered to the respiratory tract was retained. The immediate local effects of insulin aerosol administration on the lungs were evaluated using light microscopy. No adverse effects were observed at histopathologic examination of the lung tissue.

This study shows a high penetration of aerosol to the peripheral parts of the lung and efficient delivery of nebulized insulin when using the MAXIN-nebulizer.