Hydroxyethyl starch
Starch is one of the most common polysaccharides of natural origin, consisting of two polymers: branched (amylopectin – about 70%) and linear (amylose – about 30%). Due to its low toxicity, starch and its modifications are widely used in pharmaceutical preparations as an auxiliary component. The use of native amylopectin starch as the main component of a blood substitute is impossible due to its low water solubility and high viscosity. In addition, when it enters the bloodstream, starch is immediately attacked by enzymes – amylases, breaking down into low molecular weight fragments that are unable to maintain blood pressure. To avoid degradation, native amylopectin starch is subjected to chemical modification – hydroxyethylation, to obtain hydroxyethylated starch (HES).