Chitosan/gelatin as a new nano-carrier system for calcium hydroxide delivery in endodontic applications: Development, characterization and process optimization

Highlights: • In order to propose the new intracanal medicament, a new formulations of Chitosan/Gelatin was prepared and evaluated. • Modeling and optimization of calcium hydroxide loaded polymeric nanocarriers were performed using RSM. • The optimized nanocarrier formulation showed a prolonged-sustained release of calcium ions from calcium hydroxide. • The FTIR analysis indicates the presence of hydrogen bond interactions between developed system and calcium hydroxide. - Abstract: The main aim of this study is preparation, optimization and in vitro characterization of Chitosan/Gelatin nano-carriers (NCs) for calcium hydroxide (CH) to improve its therapeutic potential. The designed system can be used in the endodontic applications demanding a sustained release of calcium and hydroxyl ions. Modeling and optimization of CH loaded polymeric NCs were performed using response surface methodology (RSM) based on central composite surface statistical design. The effect of Chitosan concentration (0.1–1% w/v), Gelatin concentration (0.1–1% w/v) and CH concentration (0.05–0.4% w/v) on the particle size, polydispersity index (PDI), drug loading (DL) and encapsulation efficiency (EE) of CH loaded polymeric NCs were investigated. Optimized CH loaded polymeric NCs formulation which obtained using RSM showed spherical and smooth surface with a particle size of 292 nm, PDI of 0.32, DL of 88.8% and EE of 99%. Optimized formulation was evaluated for in vitro calcium ion release in phosphate buffer solution (PBS) at pH 7.4 for 14 days. The presence of hydrogen bonding and some intermolecular interactions between Chitosan/Gelatin polymeric materials were confirmed using Fourier transform infrared (FTIR) analysis. These interactions enable Chitosan/Gelatin NCs to load CH and maintain sustained release of Calcium ions from CH during experimental period.