Chemical Modifications of Heparin.1: Reaction of Partially N-Desulfated Heparin with Glutaraldehyde

Abstract

Purified glutaraldehyde was allowed to react with the primary amino groups generated by mild acidolysis of glucosamine N-sulfamino resi dues present in heparinic acid. The reaction yielded high molecular mass heparinoids (HMMHEP) or hydrogels, depending on experimental conditions. It was shown that a selected HMMHEP exhibited a higher anticoagulant activ ity than the starting heparin or the parent partially N-desulfated heparin. This HMMHEP degraded slowly in vitro in an aqueous medium buffered at pH = 7.4. Moreover, HMMHEP was biologically active after i.v. injection but not after s.c. and i.m. injections. Hydrogels also degraded slowly to yield biologi cally active higher molecular mass heparinoid. These findings suggested that neither N-desulfation nor coupling of glutaraldehyde adducts affected in a large extend the activity of the parent heparin.