Neutral protamine Hagedorn insulin suspension

Intermediate-acting insulins are either the neutral protamine Hagedorn insulin (NPH isophane insulin suspension) or the Lente insulin (insulin zinc suspension) the former is a suspension of the insulin-protamine-zinc complex in a phosphate buffer and the latter is a mixture of crystallized and amorphous insulin in acetate buffer. These preparations have an onset of action within about 2h, peak activity after about 4-12 h, and a duration of up to 24 h (Table 4). Commercially available mixtures of soluble insulins and isophane insulins have activities that would normally place them within the intermediate-acting category. Mixed insulin-zinc suspensions are sometimes classified as either intermediate- or long-acting as the duration of action may be up to 30 h. 

Neutral protamine Hagedorn (NPH) differs from extended insulin Zn suspension in which of the following actions ... 

Neutral Protamine Hagedorn (NPH) Insulin (Isophane Insulin Suspension)... 

The importance of zinc ions for stabilizing insulin preparations has been known since the first reported crystallization of insulin in the presenoe of zino ions in 1934 (36). Suspensions of zinc insulin were used at that time. Presently, all pharmaceutical preparations are either solutions of zino insulin or suspensions of insoluble forms of zino insulin. A longer-acting and more stable form of insulin is protamine zinc insulin, which is prepared by precipitating insulin in the presence of zinc ions and protamine, a basic protein. This precipitate is known to contain two zinc ions per insulin hexamer. A somewhat shorter-acting and more useful preparation is neutral protamine Hagedorn (NPH) insulin, which includes m-cresol... 

Semilente insulin is a suspension of amorphous insulin zinc. The onset is 1-3 hours after subcutaneous administration, reaches maximum effect in 5-10 hours and the effect lasts 10-16 hours. Isophane insulin (NPH Neutral solution. Protamine, Hagedorn s laboratoiy insulin) is an intermediate-acting preparation prepared with protamine. The maximum effect is reached in 4-12 hours and lasts 8-26 hours. Patients using these preparations who present for cardiac surgery are at increased risk for anaphylactic reactions to protamine. Ultralente insulin is a long-acting preparation formed with zinc rather than protamine. Zinc retards the release of insulin and these preparations have a duration of up to 36 hours. Protamine zinc insulin, which contains both protamine and zinc, has a duration of 28-36 hours. 

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