Аннотация:[3H]Hyaluronic acid with a molecular weight of 2.37 MDa and a specifi c radioactivity of 35 GBq/g was obtained using the tritium thermal activation method. Tritium labeled drug products of hyaluronic acid (HA) with a molecular weight of 2.37, 0.20, and 0.10 MDa were used to study their adsorption on hydroxyapatite (HAP) in two textural modifi cations: aqueous suspension and powder. Diff erences in adsorption kinetics and adsorption isotherms were observed due to variations in the interaction between polysaccharide molecules and the sorbentforms under consideration. The adsorption isotherms of HA on HAP were proven linear. It is shown that strong HA–HAP complexes are formed, and no desorption of HA into water and 0.9% NaCl solution were detected in2 days.