Preparation, Characterization and Stability Study of Eugenol-Loaded Eudragit RS100 Nanocapsules for Dental Sensitivity Reduction

Eugenol is a phenolic compound with numerous biological activities. It is widely used in dentistry to treat toothache and pulpitis. In particular, eugenol may be used for tooth whitening procedures to minimize dental sensitivity in patients. However, eugenol has some disadvantages such as its volatility, its photosensitivity, and immediate effect, which can be avoided by using pharmaceutical nanotechnology. The aim of the present study was to obtain, characterize, quantify, and evaluate the physicochemical stability of eugenol-loaded Eudragit RS100 nanocapsules. The nanocapsules (NCs) were prepared by interfacial deposition of the preformed polymer method. The NCs were characterized through morphological and spectroscopic studies. The encapsulation efficiency was achieved by quantifying the non-encapsulated eugenol using a previously developed and validated analytical method. The physicochemical stability of NCs was assessed at predetermined time intervals for 90 days after preparation. The nanocapsules were successfully prepared by the chosen method and had a predominantly spherical shape with a smooth surface. The mean size, the polydispersion index, and the zeta potential were in agreement to literature data. Infrared spectra ensured that the nanoencapsulation process did not result in chemical reactions between the drug and the polymer. The formulations showed encapsulation efficiency higher than 90% and remained stable after 60 days of preparation. Thus, eugenol-loaded Eudragit RS100 nanocapsules may be further considered as an alternative formulation for dental sensitivity in order to provide a controlled release, a decreased toxicity, and a better dental sensitivity relief.