Adsorption of tranexamic acid on hydroxyapatite: Toward the development of biomaterials with local hemostatic activity.

This work proposes to combine tranexamic acid (TAX), a clinically used antifibrinolytic agent, and hydroxyapatite (HA), widely used in bone replacement, to produce a novel bioactive apatitic biomaterial with intrinsic hemostatic properties. The aim of this study was to investigate adsorptive behavior of the TAX molecule onto HA and to point out its release in near physiological conditions. No other phase was observed by X-ray diffraction or transmission electron microscopy, and no apparent change in crystal size was detected. The presence of TAX on the powders was lightly detected on Raman spectra after adsorption. The adsorption data could be fitted with a Langmuir-Freundlich equation, suggesting a strong interaction between adsorbed molecules and the formation of multilayers. The concentration of calcium and phosphate ions in solution remained low and stable during the adsorption process, thus ion exchange during the adsorption process could be ruled out. The release of TAX was fast during the first hours and was governed by a complex process that likely involved both diffusion and dissolution of HA. Preliminary aPTT (activated partial thromboplastin time) hemostasis tests offered promising results for the development of osteoconductive apatitic biomaterials with intrinsic hemostatic properties, whether for dental or orthopedic applications.