Objective: Nasal insulin administration is a potential route for intensive insulin management, less invasive and more rapid than subcutaneous injections. Previous studies have shown poor bioavailability (less than 15%) with nasal insulin administration with various absorption enhancers. The aim of the study was to evaluate in type 1 diabetic patients, the metabolic efficacy and local tolerance of a new gelified sprayed nasal insulin containing glychocolate and methylcellulose as absorption promoters.
Material and methods: The study was conducted in 16 type 1 diabetic patients (HbA1c 8.6+/-0.2%) in a cross-over trial including 2 six month randomized periods: a) NPH twice daily + 3 pre-prandial nasal insulin doses + nasal supplementation in case of unexpected hyperglycaemia; b) NPH twice daily + 3 pre-prandial regular insulin injections. End points were HbA1c levels, hypoglycaemic episodes and tolerance evaluated at month 0, 2, 6 and 8 on clinical symptoms and objective nasal assessments.
Results: Four patients were withdrawn because of nasal burning (3 cases) and persistent sinusitis (1 case), and one patient had purulent sinusitis at the month 6 examination. At month 6, HbA1c levels were comparable (8.3 +/- 0.1 vs 8.6 +/- 0.1%, m +/- SEM, NS) for nasal and subcutaneous period respectively. The number of hypoglycaemic events was identical during the 2 periods (88 episodes). Nasal tolerance with the gelified form was better than with the already reported lyophilized form but, when present, symptoms were more marked, suggesting a potentiating additional role of methylcellulose excipient on nasal intolerance.
Conclusions: 1) Gelified nasal insulin is as efficient as subcutaneous regular insulin in type 1 diabetic patients. 2) Other galenic forms should be investigated to improve nasal tolerance and bioavailability.