Changes in serum IRI, CPR and glucose were determined in 18 healthy adults after spraying of porcine crystallin insulin to nasal or sublingual mucous membrane. Ten, 30 or 50 U porcine crystallin insulin was dissolved in 0.1 ml 0.9% NaCl containing 1 % sodium glycocholate ph 7.6. When it was applied to nasal mucous membrane, there were significant decreases in serum glucose and CPR levels. There was a positive correlation between the peak serum IRI levels and doses of insulin applied. However, when it was applied to the sublingual mucous membrane, there were no measurable increases in serum IRI levels.
When sodium glycocholate was omitted, no measurable increas in serum IRI levels was observed. Substitution of sodiun glycocholate with other surface activating agents such as lysozyme chloride, HCO-60, Byco-E, did not facilitate the absorption of insulin at all. Ursodeoxycolate was effective in facilitating absorption of insulin from nasal mucous membrane, but this agent was associated with marked local irritation.
The results showed that significant amount of insulin was absorbed from nasal mucous membrane when it was dissolved in a solution contaning sodium glycocholate. This route of administration of insulin may be useful under certain clinical circumstances.