Insulin delivery in nosedrops: new formulations containing alkylglycosides

Insulin was administered to rats via nosedrops in the presence or absence of various alkylglycosides; systemic insulin absorption was measured as a fall in blood D-glucose concentration in animals made hyperglycemic by xylazine/ketamine anesthesia. Nosedrops (0.04 ml) containing alkylglycosides or regular porcine insulin alone were without effect. Nosedrops containing both a small amount of alkylglycoside (0.03-0.50%) and insulin (2 U regular porcine) caused a rapid decrease in blood D-glucose levels and a concomitant increase in serum immunoreactive insulin levels. The maximal hypoglycemic response was observed between 60 and 120 min after delivery of nosedrops. Decylmaltoside was less effective at enhancing systemic insulin absorption than dodecylmaltoside, tridecylmaltoside, or tetradecylmaltoside, whereas octylmaltoside was totally ineffective. Dodecylsucrose, a compound which differs from dodecylmaltoside only in one carbohydrate residue, had a similar effect on blood D-glucose values when it was included in the nosedrop formulation with insulin. Decylsucrose was considerably less potent than dodecylsucrose at enhancing systemic absorption of insulin. Nonylglucoside was effective at promoting insulin absorption from nosedrops only when used at higher doses (0.25-0.50%), whereas heptylglucoside and hexylglucoside were ineffective. These results indicated that nosedrops containing insulin plus an extremely low concentration (0.03%) of an absorption-enhancing agent such as tetradecylmaltoside can be used to lower blood D-glucose values.