Oral Insulin: A Comparison With Subcutaneous Regular Human Insulin in Patients With Type 2 Diabetes
OBJECTIVE
To determine the pharmacokinetic and pharmacodynamic properties of an oral insulin (OI) formulation compared with subcutaneously injected regular human insulin (RHI).


RESEARCH DESIGN AND METHODS
Ten male patients with type 2 diabetes (means +/- SD; A1C 7.0 +/- 1.1%; BMI 28.3 +/- 2.7 kg/m(2)) received either 300 units of insulin combined with 400 mg of delivery agent orally or 15 units RHI subcutaneously under isoglycemic clamp conditions.


RESULTS
Maximum insulin concentration was greater and onset of action was faster with OI (C(max) 93 +/- 71 vs. 33 +/- 11 microU/ml; AUC(GIR)((0-1h)) 173 +/- 86 vs. 27 +/- 32 mg/kg; P < 0.05). Mean insulin concentration and glucose infusion rate returned to baseline within 3 h after OI administration. Relative bioavailability of OI was 7 +/- 4% (1st 2 h).


CONCLUSIONS
This proof-of-concept study demonstrated that absorption of OI is feasible under fasting conditions. OI has a fast onset and a short duration of action but also shows a rather high between-subject variability in absorption.