Insulin therapy formulations

To facilitate multiple subcutaneous injections of insulin, particularly during intensive insulin therapy, portable pen-sized injectors have been developed. These contain cartridges of insulin and replaceable needles. Disposable insulin pens are also available for selected formulations. These include regular insulin, insulin lispro, insulin aspart, NPH insulin, and premixed 70%/30% and 50%/50% NPH/regular, 75% NPL/25% lispro, 50% NPL/50% lispro, and 70% NPA/30% aspart insulin. They have been well accepted by patients because they eliminate the need to carry syringes and bottles of insulin to the workplace and while traveling. 

In conventional intensified insulin therapy (MDI) using the basal-bolus approach with MDI, continuous basal insulin supply is obtained by once- or twice-daily subcutaneous injections of longer-acting preparations, supplemented by mealtime injections of more rapid-acting formulations. 

As a result of derivatization of insulin during isolation and purification steps, and during storage of the pharmaceutical preparations, therapeutic insulin contains smaller amounts of desamido insulins, covalent insulin dimers, and other insulin derivatives. Physical and chemical stability of insulin in formulations for injection therapy has recently been reviewed in a previous volume of this series (Brange and Langkjser, 1993) and in a monograph (Brange, 1994). 

Formulate appropriate doses of medications involved in patient therapy and revise as needed. Patient parameters may change frequently, thus requiring different doses and/or medications. Examples include antibiotic therapy, sedatives, insulin, fluids, or vasopressors. 

Regular insulin typically is given subcutaneously, often in combination with an intermediate-or long-acting preparation. Special buffered formulations of regular insulin are available for use in subcutaneous infusion pumps that are less likely to crystallize in the tubing during the slow infusion associated with this type of therapy. 

The most common pancreatic disease requiring pharmacologic therapy is diabetes meliitus, a deficiency of insulin production or effect. Diabetes is treated with several formulations of insulin (all administered parentertdly at present) eind with four types of oral antidiabetic agents (Figure 41-1). 

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