Box-Behnken Design of Experiment Assisted Development and Optimization of Bendamustine HCl loaded Hydroxyapatite Nanoparticles

Background: Bendamustine HCl, an antineoplastic drug, has a very short life of about 40 minutes which necessitates administration of large doses which leads to increased side effects as well as costs. Objective: The present work describes the fabrication, optimization, and evaluation of bioactive hydroxyapatite nanoparticles to achieve sustained delivery of bendamustine HCl. Methods: Hydroxyapatite nanoparticles (NPs) were prepared by the wet chemical precipitation method by reacting a calcium and phosphate precursor and the reaction was optimized via Box-Behnken DOE. The drug was loaded on particles by physical adsorption. Various analytical studies were performed on the fabricated nanoparticles in addition to biodistribution studies to establish the physicochemical and biological characteristics of the designed formulation. Results: pH of the reactant solution was found to have a more profound effect on the particle size and size distribution in comparison to reactant concentration. The particles were found to have a spherical morphology by SEM. Size of the blank and drug-loaded nanoparticles was found to be 130 +/- 20 nm by TEM. Energy Dispersive X-ray Spectroscopy (EDS) studies confirmed the presence of hydroxyapatite as the dominant phase while DSC studies indicated the presence of the drug in its amorphous form after its adsorption on NPs. Tissue distribution studies further suggested that the majority of drug concentration was released in blood rather than the other organs implying low organ toxicity. Conclusion: Bendamustine loaded hydroxyapatite nanoparticles were successfully optimized and fabricated. Favorable results were obtained in in vitro, in vivo, and analytical studies.