HYALURONIC-ACID ESTER MICROSPHERES AS A NASAL DELIVERY SYSTEM FOR INSULIN

The use of hyaluronic acid ester microspheres for the intranasal delivery of insulin was investigated in sheep. The formulations were based on two types of microspheres produced from the same polymer but using different stabilising agents. Furthermore, the effect of varying the dose of microspheres was also assessed. For comparison, insulin was also administered nasally as a simple solution and subcutaneously as an injectable preparation. Overall, the microsphere system produced large and significant increases in the nasal absorption of insulin similar to what has been obtained for bioadhesive starch microspheres. Generally, the increase in nasal absorption of insulin (AUC and C-max) achieved by the microsphere system was found to be independent of the dose of microspheres in the range 0.5-2.0 mg/kg. The mean relative bioavailability of the developed system was found to be 11% when compared with insulin administered by the subcutaneous route.