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Calcium hydroxide loaded PLGA biodegradable nanoparticles as an intracanal medicament.

AIM
To develop a formulation in which calcium hydroxide (Ca(OH)₂) was successfully loaded into poly lactic-co-glycolic acid (PLGA) biodegradable nanoparticles (NPs) to be used in the field of Endodontics as an intracanal medicament, including NPs optimization and characterization, plus drug release profile of the NPs compared to free Ca(OH)₂. Additionally, comparison of the depth and area of penetration of the NPs inside the dentinal tubules of extracted teeth against the free Ca(OH)₂ was carried out.


METHODOLOGY
Ca(OH)₂ NPs were prepared using the solvent displacement method. Optimization of NPs was carried out with a central composite design to obtain a final optimized formulation. The morphology of the NPs was examined under transmission electron microscopy (TEM), and characterization was done by X-ray diffraction (XRD), fourier transform infrared (FTIR) and differential scanning calorimetry (DSC). The drug release profile of the Ca(OH)₂ NPs and free Ca(OH)₂ was evaluated up to 48 hours. Finally, the depth and area of penetration inside the dentinal tubules of extracted teeth was examined for both the Ca(OH)₂ NPs and free Ca(OH)₂ using the Mann-Whitney U test to determine any significant differences.


RESULTS
Utilizing the optimized formulation, the Ca(OH)₂ NPs had an average size below 200 nm and polydispersity index lower than 0.2, along with a highly negative zeta potential and suitable entrapment efficiency percentage. The spherical morphology of the Ca(OH)₂ NPs was confirmed using TEM. Results of the XRD, FTIR and DSC, revealed no interactions and confirmed that the drug was encapsulated inside the NPs. The drug release profile of the Ca(OH)₂ NPs exhibited a prolonged steady release that remained stable up to 48 hours with higher concentrations than the free Ca(OH)₂. After examination by confocal laser scanning microscopy, Ca(OH)₂ NPs had a significantly greater depth and area of penetration inside dentinal tubules compared to the free drug.


CONCLUSIONS
Ca(OH)₂ loaded PLGA NPs were successfully optimized and characterized. The NPs exhibited a prolonged drug release profile and superior penetration inside dentinal tubules of extracted teeth when compared to Ca(OH)2 .