Dextran is a complex branched glucan (polysaccharide derived from the condensation of glucose. IUPAC defines dextrans as "Branched poly-α-d-glucosides of microbial origin having glycosidic bonds predominantly C-1 → C-6".[1] Dextran chains are of varying lengths (from 3 to 2000 kilodaltons).
The polymer main chain consists of α-1,6 glycosidic linkages between glucose monomers, with branches from α-1,3 linkages. This characteristic branching distinguishes a dextran from a dextrin, which is a straight chain glucose polymer tethered by α-1,4 or α-1,6 linkages.
Function
An uncommon but significant complication of dextran osmotic effect is acute renal failure. The pathogenesis of this renal failure is the subject of many debates with direct toxic effect on tubules and glomerulus versus intraluminal hyperviscosity being some of the proposed mechanisms. Patients with history of diabetes mellitus, renal insufficiency, or vascular disorders are most at risk. Brooks and others recommend the avoidance of dextran therapy in patients with chronic renal insufficiency.
Application
Medicinally it is used as an antithrombotic (antiplatelet), to reduce blood viscosity, and as a volume expander in hypovolaemia. Dextran 70 is on the WHO Model List of Essential Medicines, the most important medications needed in a health system.
1, It is used in some eye drops as a lubricant.[9] and in certain intravenous fluids to solubilize other factors, such as iron (in a solution known as Iron Dextran).
2, Intravenous solutions with dextran function both as volume expanders and means of parenteral nutrition. Such a solution provides an osmotically neutral fluid that once in the body is digested by cells into glucose and free water. It is occasionally used to replace lost blood in emergency situations, when replacement blood is not available, but must be used with caution as it does not provide necessary electrolytes and can cause hyponatremia or other electrolytedisturbances.
3, It also increases blood sugar levels.
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