This article is a clinical report on the use of modified protamine insulin (NPH-50)—first, what it is; second, why it is indicated; third, how does it differ from present market insulins; fourth, what has been the experience of the Joslin Clinic in its use; fifth, what technics have been employed in its administration, and, sixth, what are its failures as well as its successes?
Insulin of the NPH-50 type contains protamine modified by crystallization. Neutral in reaction, it is designated N; protamine, it is termed P; improved by Hagedorn, it is named H; modified by the addition of 0.50 mg. of crystallized protamine for every 100 units of insulin, it is tagged 50—therefore, NPH-50 insulin.
New modifications of insulin are being and should be sought. Wonderful though insulin is, the forms now available have three obvious defects; first, their administration is parenteral; second, their time of action is too slow,