Effects of Molar Substitution on the Mobility of Hydroxyethylstarch Macromolecules in Solution

Abstract

The effects of molar substitution of hydroxyethylstarch on the macromolecule mobility in solution were studied by diffusion-ordered NMR spectroscopy (¹H-DOSY) to measure mean self-diffusion coefficients of hydroxyethylstarch with different levels of modification of amylopectin. Molar substitution of hydroxyethylstarch had the opposite effect on macromolecule mobility from that of branching of the polymer chain. Standard samples and medicinal hydroxyethylstarch substances were shown to be nonuniform in terms of the degree of molar substitution. Inclusion of an additional parameter – molar substitution – into regression equations was found to increase the accuracy of measurement of the molecular weight of hydroxyethylstarches using analytical chemistry transport methods.