An iron-containing composition suitable for parenteral administration in human and veterinary medicine consisting essentially of an aqueous solution of a complex of iron, said complex containing iron bound to a physiologically innocuous, water swellable polymer which is the reaction product of I. at least one hydroxy carboxylic acid selected from the group consisting of arabonic acid, gluconic acid and glucoheptonic acid and salts and lactones derivable therefrom; Ii. at least one polyhydric alcohol selected from the class consisting of glycerol, polyglycerols, tetritols, pentitols, hexitols, heptitols, with alkyl groups containing from 1 to 5 carbon atoms, partially etherified derivatives of said polyhdydric alcohols, and with hydroxyalkyl groups containing from 1 to 5 carbon atoms partially etherified derivatives of said polyhydric alcohols; and Iii. at least one polymerizing agent selected from the group consisting of dihalohydrins and epihalohydrins and diepoxides derivable therefrom, and mixtures thereof.
An aliphatic polyester is provided which is manufactured by a process comprising a step of hydrolyzing cellulose so as to form D-glucose, a step of forming gluconolactone represented by the formula (II) from the D-glucose, and a step of performing ring-opening polymerization of the gluconolactone so as to form an aliphatic polyester represented by the formula (I). ##STR1## In the formulas above, R represents a hydrogen atom, an acetyl group, or a linear or a branched alkyl group having 1 to 3 carbon atoms, and the subscript n is an integer of 10 to 6,000.
