Flavonoids-loaded Polymeric Nanoparticles in Dental Adhesives: Synthesis and characterization for the development of new therapeutic systems

The use of nanoparticles as drug carriers has been proposed to provide a safe and effective slow drug release. This study evaluated the synthesis and characterization of nanoparticles loaded with the flavonoids naringin (NAR) and quercetin (QER). Nine formulations (n = 9) were created by nanoprecipitation technique using varying concentrations of polycaprolactone and Tween 80 to determine the most suitable solution containing either NAR or QER nanoparticles. After centrifuging the formulations, the precipitated portion was subjected to Zetasizer to determine the polydispersity index (PDI) and molecular size, as well as to Field Emission Scanning Electron Microscopy (FE-SEM) analysis. The NAR and QER formulations considered suitable for the intended purposes were lyophilized and subjected to Fourier Transform Infrared (F-TIR) analysis. The supernatant was analyzed using UV–vis to determine the encapsulation efficiency (%EE). The formulation had an average particle size ranging from 181.1 nm to 221.0 nm for NAR and from 170.0 nm to 503.5 nm for QER formulation. FE-SEM analysis confirmed these findings, as nanoparticle sizes ranged from 103.72 to 334.77 nm for NAR and 73.89–470.30 nm for QER. The PDI ranged from 0.142 to 0.290 and from 0.242 to 0.732 for NAR and QER, respectively. F-TIR analysis showed no apparent chemical interaction between the flavonoids and components of the formula. UV–vis analysis showed that NAR and QER achieved 89.09 % and 96.40 % %EE, respectively. Nanocapsules containing NAR and QER showed no signs of incompatibility or chemical interaction among components. The inclusion of flavonoid nanoparticles into the composition of adhesive systems may be a strategy to deliver therapeutic molecules into dentin in dental restorations.