Chemometric evaluation of mechanochemical transformation kinetics and controlled release characteristics of bio-essential metal-containing hydroxyapatite-related nanoparticles using powder X-ray diffractometry and near-infrared spectroscopy

Calcium-deficient hydroxyapatite-containing zinc (ZnAP) nanoparticles with controlled zinc release properties were efficiently synthesized in a planetary ball mill from calcium hydrogen phosphate dihydrate, calcium oxide, and zinc oxide in a wet mechanochemical process. The wet mechanochemical transformation process, measured using powder X-ray diffraction (PXRD) and near-infrared spectroscopy (NIR), was quantitatively decomposed into raw material, intermediate, and final product (ZnAP)/time plots using alternating least squares analysis. All mechanochemical transformation process datasets evaluated using the PXRD and NIR methods were theoretically fitted to sequential reaction kinetics model equations using the nonlinear least squares method. The fitted transformation rate constants of the chemical model based on the PXRD and NIR datasets exhibited reasonable values. The amount of zinc released (D 10 ) in the milled ZnAP injection suspension was measured in pH 6.2 buffer at 37 °C for 10 minutes as a therapeutical index. Optimized calibration models that were constructed based on the PXRD and NIR data using partial least squares regression analysis were used to accurately predict the D 10 of the milled products. • Zn-containing apatite-nanoparticles were synthesized in wet mechanochemical process. • Wet-process was monitored using X-ray diffraction and near-infrared spectral methods. • Process data of the milled products was decomposed three sources using ALS analysis. • All process datasets were fitted to sequential reaction kinetics model equations. • Zn release characteristics of milled products could be predicted using PLSR analysis.