Study on the host-guest interactions during caffeine encapsulation into zeolite

Abstract

The objective of this study was to investigate the equilibrium and kinetics behavior, sorption mechanism and host-guest interactions during caffeine (CAF) encapsulation in natural zeolite. The chemical, spectral and morphological properties of the newly obtained drug-carrier system were analyzed. Zeolite surface chemistry and morphology were characterized by determination of pH of zero charge, FT-IR and digital microscopy analyses. Equilibrium and kinetic sorption experiments and modeling were conducted to assess zeolite potential. Satisfactory extend of CAF encapsulation in the zeolite matrix (E 36.4%) was obtained. The probable host-quest interactions include Van der Waals interactions, H-bonds and chemical interactions between CAF functional groups and zeolite silanol groups, as well as parallel intraparticle diffusion of drug molecules in the mesopores of the mineral particles. The analyses of the experimental results indicated that natural zeolite could be successfully applied for encapsulating CAF.