RESUMEN
The incorporation of active compounds into polymeric matrices using traditional methods has several drawbacks mainly due to the high volatility and thermal sensitivity of these substances. A solution to this problem could be the incorporation of bioactive compounds forming inclusion complexes as a strategy to improve the chemical stability, bioactivity and achieve controlled release. In this work, ß-cyclodextrin/carvacrol inclusion complex was prepared by spray drying to be incorporated into poly(lactic acid) (PLA) and Mater-Bi® films by supercritical CO2 impregnation. The impregnation process was carried out at pressures of 10, 15 and 20â¯MPa and at 40⯰C. Both polymers showed the highest amount of incorporated inclusion complex at 15â¯MPa, where the percentage of impregnation varied from 0.6â¯% to 7.1â¯% in Mater-Bi® and PLA, respectively. Release tests for PLA films impregnated with inclusion complex showed a slow release of the active compound, which did not reach equilibrium after 350â¯h under the experimental conditions. This prolonged release was not observed in Mater-Bi® due to the lower incorporation of the inclusion complex. The release rate was described herein by a comprehensive phenomenological model considering the decomplexation kinetics combined with the equilibrium and mass transfer expressions.