Sodium caseinate films modified using halloysite: Physicochemical characterization and drug permeability studies

Abstract

Modification of sodium caseinate (SC) films by adding halloysite (HS) was investigated in this study. SC films with HS added in different ratios were prepared, and the physicochemical properties and drug permeability of the films were characterized. Acetaminophen was used as a model drug, and parabens served to evaluate the effect of the molecular weight of permeants through the films. This study revealed that SC could interact with HS through hydrogen bonding between the amine and amide groups of SC and the hydroxyl groups on the inner or outer tubular HS. The SC-HS films presented as continuous sheets and had a similar transparency as the SC films. The thermal stability of the SC films could be enhanced by adding HS. Incorporation of HS caused a reduction in puncture strength and elongation of the dry SC films, whereas strength enhancement of the wet SC-HS films in acidic medium was found. The SC-HS films had lower water uptake and delayed drug permeation across the films in acidic medium. Moreover, the drug permeations across the SC and SC-HS films were dependent on the molecular weight or alkyl chain of parabens that impacted drug diffusion and partition processes through the films. The new knowledge obtained can be helpful for the development of film coating material based on SC-HS composites for modified-release tablets.