Aims/hypothesis  

The pharmacokinetic and pharmacodynamic properties of biphasic insulin aspart (BIAsp 30) (30% soluble, 70% protaminated insulin aspart [IAsp]) and insulin glargine (IGlarg) were compared.

Methods  

Twelve people with type 2 diabetes took part in two 24-h isoglycaemic clamp studies, 1 week apart. Patients were randomised to treatment with 0.5 U/kg of BIAsp 30 (0.25 U/kg at 08.30 h and 0.25 U/kg at 20.30 h) or 0.50 U/kg IGlarg at 08.30 h. Both insulins were given by subcutaneous injection into the anterior abdominal wall. The plasma glucose, glucose infusion rates, plasma insulin and C-peptide concentrations were measured.

Results  

All 12 patients were men; mean (±SD) age was 58.8 (8.9) years, BMI 31.0 (3.0) kg/m² and HbA_1c 7.1 (0.6)%. Plasma glucose was constant throughout the 24-h clamp period. After each injection of BIAsp 30, glucose infusion rates increased, reaching a distinct peak approximately 3–5 h after injection. A much flatter postinjection profile was observed following IGlarg administration. Plasma insulin concentrations rose rapidly after each injection of BIAsp 30, reaching a distinct peak after approximately 2–3 h. A flatter plasma insulin profile reached a plateau approximately 6–16 h after IGlarg administration. Plasma C-peptide fell below baseline after both injections of BIAsp 30 but remained unaltered after IGlarg injection.

Conclusions/interpretation  

The pharmacodynamic and pharmacokinetic profiles were 34 and 28%, respectively, higher following equivalent doses (0.5 U/kg) of BIAsp 30 given as two split doses than following IGlarg given as a single daily dose.