Bronchopulmonary absorption of aerosolised insulin

Seven non-insulin dependent diabetes mellitus (NIDDM) patients aged 48 to 78 years, inhaled approximately 10 to 20 units of aerosolised insulin (human actrapid) by nebuliser. In 5 cases, approximately 10 units of insulin aerosol inhalation was given 4 hours after breakfast. Blood glucose level started falling after 15 minutes with a maximum fall at 45 minutes to 1 hour. In 2 cases insulin aerosol inhalation was given 2 hours after lunch. The first dose of 10 units of insulin did not show any significant change in blood glucose level at 30 minutes. A second dose of 10 units of insulin aerosol was inhaled after 30 minutes and blood glucose level started falling in a pattern similar to the first group of patients. The first dose appears to withhold the rise of blood glucose in the postprandial phase and the second dose lowers the blood glucose level. The result is compared with placebo inhalation and there is a significant fall of blood glucose level with insulin aerosol inhalation. It admits of little doubt that insulin is absorbed from the bronchopulmonary mucosa.