Subcutaneous use of regular human insulin (Novo): pharmacokinetics and continuous insulin infusion therapy

The absorption kinetics of human insulin (Novo) were studied and compared with those of purified porcine insulin preparations in seven healthy men. The absorption of insulin after subcutaneous injection of human insulin (Actrapid, Novo) was significantly accelerated and its hypoglycemic effect significantly stronger when compared with porcine insulin (Actrapid). No differences in the absorption kinetics were observed using human insulin (Monotard, Novo) and porcine insulin (Monotard) preparations, respectively. A clinical trial was designed to determine whether the pharmacokinetic differences were relevant for the clinical use of regular human insulin. The efficacy of human and porcine insulin (Actrapid) was tested in a double-blind crossover protocol in 12 type I diabetic patients treated with continuous subcutaneous insulin infusion. Near-normoglycemia was achieved with both types of insulin. Diurnal blood glucose values and excursions, insulin requirements, the frequency of mild hypoglycemic episodes, and the carbohydrate content of the diet were essentially identical. Thus, the differences between the absorption of human insulin and porcine regular insulin from a subcutaneous depot as observed in the pharmacokinetic studies in normal man do not appear to be relevant in the clinical practice of the subcutaneous insulin replacement therapy in type I diabetes mellitus at near-normoglycemia.