Strategies to Enhance Yield of Wet-Synthesized Hydroxyapatite Nanocrystals and Consequences for Drug-Release Kinetics

Efficient production of nanocrystalline hydroxyapatite with desirable properties is a key focus in research on nanomaterials based on this mineral. It has been shown that, in the widely used wet synthesis method, fundamental factors such as the choice of calcium source and the type of post-reaction suspension maturation can play a crucial role. This study examines the influence of these two factors on parameters including synthesis yield, crystal size and morphology, material crystallinity and specific surface area, variations in OH group content, and the Ca/P molar ratio. The effect of these factors on drug release from tablets containing the synthesized hydroxyapatites was also evaluated. The results clearly demonstrate that calcium acetate decreases the synthesis yield of hydroxyapatite nanocrystals, particularly under dynamic maturation conditions. Moreover, this calcium source exerts the strongest influence on the drug release profile from tablets incorporating the obtained hydroxyapatite.