Intermediate-acting insulin preparations: NPH and lente.

Physicochemically, NPH and lente insulins differ in size of crystals, content of protamine and zinc, and often in species composition, since lente always contains beef insulin. The duration of the hypoglycemic effect of lente insulin seems to be longer than 24 h, whereas that of NPH insulin does not exceed 24 h when given in amounts of 0.2-0.3 U/kg body wt. Moreover, NPH and lente insulins differ in their ability to form stable mixtures with neutral insulin solutions, since only NPH insulin can be mixed with regular insulin without changing the specific course of effect of regular insulin. Highly purified porcine NPH and the lente-like porcine insulin preparation. Monotard, do not seem to differ regarding side effects (lipoatrophy, immunogenicity). However, highly purified lente insulin (containing beef insulin) seems to be more immunogenic than highly purified porcine NPH insulin.