Twelve subjects with type 1 diabetes received an INH dose (50 IU) using an inhaler on 4 visits and 6 U insulin lispro (LIS) sc on a separate visit to assess relative bioavailability (FREL) of INH. The inhaler was configured to generate insulin aerosol particles sized 3.5-4.0 μm (low output mesh; LOM), 4.3-4.8 μm (medium output mesh; MOM) or 5.0-5.5 μm (high output mesh; HOM) during low inspiratory flow. To assess within subject variability, MOM was used twice. Pharmacokinetics (PK) were measured up to 8 hours after dosing.