Pharmacokinetic Properties of Fast-Acting Insulin Aspart Administered in Different Subcutaneous Injection Regions

Fast-acting insulin aspart (faster aspart) is insulin aspart set in a new formulation with faster initial absorption after subcutaneous administration. This study investigated the pharmacokinetic properties, including the absolute bioavailability, of faster aspart when administered subcutaneously in the abdomen, upper arm or thigh.

In a randomised, open-label, crossover trial, 21 healthy male subjects received a single injection of faster aspart at five dosing visits: 0.2 U/kg subcutaneously in the abdomen, upper arm and thigh, intramuscularly in the thigh and 0.02 U/kg intravenously. Blood sampling for pharmacokinetics was performed pre-dose and frequently thereafter until 12 h post-dose (8 h after intravenous administration).

Onset of appearance (~3 min), time to 50% of maximum concentration (t _{Early 50% Cmax}; ~20 min) and time to maximum concentration (t _max; ~55 min) were all similar between injection regions. Early exposure within the first 2 h after injection (AUC_IAsp,0-1h and AUC_IAsp,0-2h) as well as maximum concentration (C _max) were comparable for the abdomen and upper arm, but were ~25% lower for the thigh as seen previously for other mealtime insulin products. Total exposure (AUC_IAsp,0-t) was similar for the abdomen, upper arm and thigh, and absolute bioavailability was ~80% after subcutaneous administration of faster aspart in all three injection regions.

The current study supports the ultra-fast pharmacokinetic characteristics of faster aspart across different injection regions, with administration in the abdomen and upper arm resulting in greater early exposure than in the thigh. ClinicalTrials.gov identifier: NCT02089451.