Multi-day (3) In-patient Evaluation of Intradermal vs Subcutaneous Basal/Bolus Insulin Infusion

The is a single center, open-label, 2 period crossover study randomized by route (intradermal versus subcutaneous) in patients with Type 1 diabetes. Subjects will receive their insulin, basal and bolus dosages, via intradermal (ID) and subcutaneous (SC) infusion sets over a three day period.

Each subject will participate in 3 visits: a Screening Visit (V1), followed by 2 experimental intervention days (V2 and V3) to be started 2 - 21 days after screening visit. The minimum/maximum interval between study days shall be 5 to 28 days. Each subject will remain in the clinic for approximately 3 days during the experimental interventions. A final exam will be performed at the end of Visit 3.

After successful screening and enrollment subjects are admitted to the clinic. Their insulin pump and infusion set is replaced by the investigational system, a commercially available insulin pump and either the intradermal infusion set (Research Catheter Set, BD) or the subcutaneous infusion set (Quick Set, Medtronic)to include an in-line pressure transducer/recorder and insulin NovoRapid. The initial pump infusion rate is established based on the patient's known basal infusion rate and the meal bolus insulin is estimated based on the patient's known insulin sensitivity. An intravenous (in the vein) catheter line is established, blood glucose is measured at least every 2 hours overnight and insulin corrections can be implemented, if deemed necessary. The overnight and pre-prandial (before meal) target range is 70-160 mg/dl, although the procedure will continue as planned if the patient is outside the range. It should be the goal not to give any IV glucose or insulin at all, and not to change basal insulin settings for at least 2 hours before the meal. The breakfast meal will be a high GI (60g carbohydrates) solid meal, to be consumed within 15 minutes and followed for a period of 6 hours of blood sampling for glucose and insulin levels. Lunch will be served as standardized mixed meal, and followed for a period of 4-6 hours. This procedure is repeated on days 2 and 3 whereas the breakfast and lunch meal as well as the insulin dose to cover the meal are the same. A light evening dinner is served every day, composition and insulin dose to be recorded. On day three after the 4 hour period following lunch the catheter will be removed, catheter and site assessments will be documented and an ultrasound observation of the infusion site (skin thickness and SC) versus an adjacent control site will be performed within 10 min after removal of the infusion set. Glucose rescue, if necessary, will be administered orally (juice, 200 mL). Insulin correction boli should be delivered via the investigational infusion set.