Nanopartículas por complexação polieletrolítica à base de goma do cajueiro modificada/quitosana para encapsulamento do acetato de timila.

Abstract

In this work, nanoparticles were produced based on chitosan and modified cashew gum using the technique of polyelectrolytic complexation. Two derivatives of cashew gum were obtained, one carboxymethylated and the other sulfated. The modifications were confirmed by FTIR and 13C NMR. The carboxymethylated derivative exhibited a chain degradation confirmed by gel permeation chromatography, while the sulfated derivative showed no change in its peak molar mass. The nanoparticles showed the characteristic bands of the starting polyelectrolytes in the infrared spectrum. In distilled water, both systems presented a nanometric scale. The nanoparticles with carboxymethylated cashew gum showed between 150 and 195 nm in size, while the nanoparticles with sulfated cashew gum were between 145 and 285 nm in size. The smallest nanoparticles were the QTGCM75 (system with chitosan and carboxymethylated cashew gum with n+/n-=0.75) and QTGCS75 (system with chitosan and sulfated cashew gum with n+/n-=0.75) systems with 154 and 149 nm, respectively. As for the zeta potential, the best system was the QTGCM75, with -22.2 mV. Thus, the QTGCM75 system was selected to proceed with the encapsulation of thymol acetate, obtaining an encapsulation efficiency of 41% and loading capacity of 24%. The system presented a controlled release profile, releasing 97% of the encapsulated thymol acetate in 120 hours. As for the release kinetics, the system was adapted to the Korsmeyer-Peppas kinetic model, indicating a release mechanism by Fickian diffusion and the Higuchi model. The nanoparticles showed promising characteristics for the encapsulation of thymol acetate.