Synthesis of Nanohydroxyapatite via Euclea natalensis-Mediated Precipitation for Enhanced Artemisinin Loading and Release

Developing drug delivery systems that mitigate difficulties and/or improve distribution and efficiency has been of great interest in recent years. In this work, a nanohydroxyapatite/Euclea natalensis system was designed via precipitation with three experimental parameters (reaction temperature, amount of template, and reaction drip-rate) for improved loading and release of the antimalarial drug artemisinin. Characterization confirmed synthesized nanomaterials with average particle sizes ranging from 17.09 to 27.67 nm. Calcination was found to reduce the surface area, pore size, and pore volume of the samples. The optimal spherical morphology was achieved using 1.20 g of material and a reaction drip rate of 1.5 mL/min at 50 °C, followed by calcination. However, greater adsorption efficiency was observed in the non-calcined samples due to higher values in surface area, pore size, and pore volume, with an increase in efficiency of up to 79.14% with the modification of the molar ratio of artemisinin/hydroxyapatite. There was up to 13.39% increase in drug loading efficiency in the sample with the template compared to the sample without the template, using a 1:2 molar ratio of artemisinin to nanohydroxyapatite. A controlled release between 20 min and 1560 min was satisfactorily obtained, following the Higuchi kinetic model.