Pharmacokinetics and postprandial glycemic excursions following insulin lispro delivered by intradermal microneedle or subcutaneous infusion.

Background: Intradermal (ID) delivery has been shown to accelerate insulin pharmacokinetics (PK). We compared the PK and pharmacodynamic (PD) effects of insulin lispro administered before two daily standardized solid mixed meals (breakfast and lunch), using microneedle-based ID or traditional subcutaneous (SC) delivery.

Method: The study included 22 subjects with type 1 diabetes in an eight-arm full crossover block design. One arm established each subject's optimal meal dose. In six additional arms, the optimal, higher, and lower doses (+30%, -30%) were each given ID and SC delivery, in random order. The final arm assessed earlier timing for the ID optimal dose (-12 versus -2 min). The PK/PD data were collected for 6 h following meals. Intravenous basal regular insulin was given throughout, and premeal blood glucose (BG) adjusted to 115 mg/dl.

Results: The primary end point, postprandial time in range (70-180 mg/dl), showed no route-based differences with a high level of overall BG control for both SC and ID delivery. Secondary insulin PK end points showed more rapid ID availability versus SC across doses and meals (∆Tmax -16 min, ∆T50rising -7 min, ∆T50falling -30 min, all p < .05). Both intrasubject and intersubject variability for ID Tmax were significantly lower. Intradermal delivery showed modest, statistically significant secondary PD differences across doses and meals, generally within 90-120 min postprandially (∆12 mg/dl BG at 90 min, ∆7 mg/dl BGmax, ∆7 mg/dl mean BG 0-2 h, all p < .05).

Conclusions: This study indicates that ID insulin delivery is superior to SC delivery in speed of systemic availability and PK consistency and may improve postprandial glucose control.