Dextran
Dextran is a polysaccharide that differs from others in that its glucose units are joined together 1:6 glucoside links. The main chain of glucose has short branches at frequent intervals which are probably joined by 1:3 and 1:4 glucoside links. The chains can be composed of about 200,000 glucose units. Many bacteria, like Leuconostoc, can synthesize dextran from sucrose, and this activity is used commercially to obtain dextran.  Dextran 40 is a sterile, nonpyrogenic preparation of low molecular weight dextran (average mol. wt. 40,000) in 5% Dextrose Injection or 0.9% Sodium Chloride Injection. It is administered by intravenous infusion.  Dextran 75 is a complex branched glucan with an average molecular weight 75000 Daltons. It is produced from certain bacteria that with α-1,6 glycosidic linkages between glucose molecules and α-1,3 linkages between branches. When labelled with technetium Tc99m, dextran 75 is intravenously administered as an imaging agent to detect and diagnose conditions in the vascular compartment such as pericardial effusion or ventricular aneurysm.