Insulin conventional

This reversed-phase chromatography method was successfully used in a production-scale system to purify recombinant insulin. The insulin purified by reversed-phase chromatography has a biological potency equal to that obtained from a conventional system employing ion-exchange and size-exclusion chromatographies (14). The reversed-phase separation was, however, followed by a size-exclusion step to remove the acetonitrile eluent from the final product (12,14). 

UK Prospective Diabetes Study (UKPDS) Group. Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33). Lancet 1998 352 837-853. 

Insulin aggregation and precipitation was an impediment to the development of implantable devices for insulin delivery as noted by several investigators working with conventional insulin infusion devices [51-54]. The potential causes of the observed aggregation and precipitation are thermal effects, mechanical stress, the nature of the materials in contact with the insulin solution, formulation factors, and the purity of the insulin preparation. 

M. Pingel, A. Volund, E. Sorensen, and A. R. Sorensen, Assessment of insulin potency by biological and chemical methods, in Hormone Drugs, U.S. Pharmacopeial Convention. Rockville, MD, 1982, pp. 200-207. 

When the combination of bedtime insulin plus daytime oral medications fails, a conventional multiple daily dose insulin regimen with an insulin sensitizer can be tried. 

By the mid-1930s, commercial insulin was being prepared by crystallization from crude porcine or bovine extracts. The crystallized preparation was generally subjected to a recrystallization step in order to further increase the product s purity. Such preparations are termed conventional insulins (Box 8.2). 

Chromatographic or electrophoretic analysis of conventional insulins generally yields three major fractions or bands a, b and c). Fraction a contains high molecular mass material which can be removed from the product by additional recrystallization steps. The major components of fraction b are proinsulin and insulin dimers, while insulin, as well as slightly modified forms of insulin (e.g. arginine-insulin and desamido-insulin), are found in fraction c. 

Additional impurities, such as glucagon, somatostatin, pancreatic polypeptide and vasoactive intestinal polypeptide, are present in most conventional insulin preparations at lower levels. The presence of such contaminants can impact upon product safety and efficacy in a number of ways. 

Conventional insulins bovine or porcine insulin purified only by crystallization... 

The higher molecular mass contaminants in conventional insulin preparations include various proteases. Such preparations are generally maintained in solution at acidic pH values (often as low as pH 2.5-3.5). This minimizes the risk of proteolytic degradation of the insulin molecules, as contaminant proteases are inactive at such pH values. 

Insulins are mostly administered subcutaneously using conventional disposable needles and syringes. To facilitate multiple subcutaneous injections... 

A conventional treatment algorithm involving clomiphene citrate (CC) followed by FSH induction of ovulation may result in a 71% cumulative single-ton live birth rate. In attempts to improve treatment outcome further and reduce complication rates, new compounds such as insulin-sensitizing agents or aro-matase inhibitors (Letrozole) are currently used increasingly. 

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