Functionalized Hydroxyapatite for Delivering Water Soluble Antibiotics in Bone Treatment Infections

This work analyses the feasibility of reprocessing bovine bone derived from livestock exploitation, a very abundant low-cost material, in a simple way, compatible with the environment, to transform it into products with high added value. This product is hydroxyapatite, the inorganic phase of bone. Improving its water absorption capacity and wettability is the other main objective. Water absorption is very important for the use of hydroxyapatite as a vehicle for water-soluble therapeutic agents for the treatment of bone pathologies. In this work, different treatments are presented with the aim of increasing water absorption in HA samples. These treatments are pyrolysis of bone up to 1100 C; a chemical treatment with phosphoric acid on pressed tablets of powdered hydroxyapatite; beads of hydroxyapatite coating with polysaccharides. This study made it possible to determine that the optimum pyrolysis temperature is close to 800 ℃, with an absorption of 20% (m/m). The chemical treatment also reached an absorption capacity of 20% (m/m). Furthermore, this treatment allowed to substantially improve the wettability by reducing the contact angle from 61 to 14°. Tests conducted on the sodium alginate coated beads resulted in an absorption of 70% (m/m). These results demonstrate the possibilities of producing hydroxyapatite for bone grafts in various forms (irregular pieces, tablets and beads) for its medical application for bone reconstruction or regeneration.