Hypoglycemic efficacy of pulmonary delivered insulin dry powder aerosol in rats

AIM: To observe the hypoglycemic efficacy of pulmonary delivery of insulin in dry powder aerosol form. METHODS: Insulin dry powder, made of insulin and other proper materials, was insufflated in rat lung from an incision in the throat. Meanwhile, insulin injection was administered to other rats. Glucose concentration in blood was determined in the following 7 h. The areas above the curve (AAC) of glucose concentration in blood were used to evaluate the efficacy. RESULTS: The percent minimum blood glucose levels, compared with the glucose levels before the administration, for pulmonary delivered insulin at the doses of 20, 10, 5, and 2.5 U/kg were 6.5 %, 16.6 %, 24.6 %, and 57.0%, respectively. The AAC of insulin 5 U/kg by pulmonary delivery was very close to that of subcutaneous administration at the same dose. There was a linear relationship between AAC and the logarithmic dose of pulmonary delivered insulin. CONCLUSION: The pulmonary delivery of insulin acts effectively and rapidly.