[Action profile of a semisynthetic human isophane zinc insulin compared with customary isophane insulin]

Addition of zinc to a protamine-isophane insulin should probably allow to lengthen its duration of action. Therefore we compared the action of this new type of insulin (NPH Zn) with that of a classical protamine-isophane NPH insulin (NPH); both were manufactured by the same firm. Five healthy volunteers were connected to an artificial pancreas. 0.6 U/Kg of insulin was injected subcutaneously in the low left quarter of the abdominal wall. Insulin action was monitored by the glucose needs delivered by the artificial pancreas working in euglycemic glucose clamp mode. Each insulin were tested in every subject at a ten day interval. The peak plasma insulin levels were observed after 2 h 30 for the NPH insulin (40 +/- 17 microU/ml) and after 3 h (47 +/- 22 microU/ml) for the NPH Zn insulin. The glucose needs reached their top levels after 2 hours (102 +/- 19 mg.kg-1 x 15 min-1) for NPH insulin and after 3 hours (98 +/- 28 mg.kg-1 x 15 min-1) for NPH Zn; the glucose needs decreased on a parallel way for both insulins but a one hour delay for NPH Zn insulin was observed. Addition of zinc to isophane NPH insulin slightly modifies the pharmacokinecinetic parameters, moving forward one hour in the glucose delivery.