Paper Title
Physicochemical Characteristics of Synthetic Hydroxyapatite Obtained in the Wet Precipitation Method

Abstract
Purpose: Due to the increasing problem of skeletal diseases, the aim of the study was to obtain synthetic hydroxyapatite (HAp) with properties beneficial for biomedical applications Methods: A wet precipitation method was used to obtain HAp. As main reagents, the ammonium dihydrogen phosphate and hydrated calcium nitrate were employed. A series of syntheses were carried out with varying parameters such as the concentration of the reagents, pH and the method of mixing. The obtained HAp was subjected to physicochemical analysis. Results: Due to the digestion of HAp in an acidic environment, the wet precipitation method performed at pH = 5.5 did not take place. In the case of the reaction conducted at pH = 8.0 a mixture of calcium phosphates including HAp, monetite and TTCP was prepared. On the other hand, process carried out at pH = 11.0 led to the synthesis of calcium phosphate with the highest phase homogeneity, that is, containing 96% of HAp. Conclusion: Changing the synthesis parameters affects the physicochemical properties of the obtained calcium phosphates. The use of selected parameters makes it possible to obtain hydroxyapatite with more favorable properties than commercially available products. Acknowledgement: The “Multifunctional biologically active composites for applications in bone regenerative medicine” project is carried out within the TEAM-NET program of the Foundation for Polish Science financed by the European Union under the European Regional Development Fund. This research was funded by Foundation for Polish Science, grant number POIR.04.04.00-00-16D7/18. Keywords - Hydroxyapatite, Calcium Phosphates, Bone Tissue Regeneration