Determination of the Degree of Esterification in Heparin Benzylates During Synthesis of Enoxaparin, a Domestic Analog of Low-Molecular-Mass Heparin

Resumo

The esterification stage of low-molecular-mass heparin (enoxaparin) production by hydrolytic depolymerization of unfractionated heparin was studied and consisted of treating previously synthesized benzethonium heparinate with benzyl chloride. The content of benzyl moieties in the synthesized heparin benzylates and their degree of benzylation were determined using HPLC, PMR, and ¹³C NMR methods. A carboxylic-acid content of 0.13 ± 0.01 mol/g in the starting heparin was calculated from these results. A new method for estimating the degree of heparin benzylation from PMR and HPLC data was proposed. The benzyl content in the heparin benzylates increased with increasing molar excess of benzyl chloride.