Synthesis and physicochemical characterization of mesoporous hydroxyapatite and its application in toothpaste formulation

The key characteristics of mesoporous hydroxyapatite, such as high porosity and expansive surface area, along with its biocompatibility with dental tissues and potential as a delivery vehicle for active ingredients, have recently garnered significant research focus. In the present study, mesoporous hydroxyapatite was synthesized using a precipitation technique and was subsequently characterized via X-ray diffraction, Fourier transform infrared, dynamic light scattering, field emission scanning electron microscopy and N₂ adsorption-desorption isotherms. The results revealed that the synthesized mesopore particles exhibited significant adsorption potential, and were thereby considered a carrier of thymol, an effective antibacterial on oral pathogens. Specifically, mesoporous hydroxyapatite's surface area and pore volume were approximately 2.66-fold and 1.95-fold higher than hydroxyapatite's. A statistically significant divergence in the release profiles of thymol from thymol-loaded mesoporous hydroxyapatite and thymol-loaded hydroxyapatite was noted, as indicated by the similarity factor (f₂ < 50). Evaluation of organoleptic parameters (taste, odor, smoothness, appearance) showed that thymol-loaded mesoporous hydroxyapatite toothpaste had superior organoleptic attributes compared to thymol-loaded hydroxyapatite toothpaste. However, both formulations were acceptable regarding pH and stability and were desirable regarding abrasiveness with no significant difference compared to the standard formulation (p > 0.05). Overall, the findings demonstrate the suitability of mesoporous hydroxyapatite as an abrasive material for developing hydroxyapatite-based toothpaste formulations.