Sodium caseinate-magnesium aluminum silicate nanocomposite films for modified-release tablets

Highlights: • Sodium caseinate (SC) interacted with magnesium aluminum silicate (MAS) via hydrogen bonding. • SC-MAS films presented exfoliated or intercalated nanocomposites. • SC-MAS films in wet state showed higher puncture strength and lower drug permeability. • SC-MAS films can be used as a tablet coating material for modifying drug release. - Abstract: The aim of this study was to investigate the effect of clay, magnesium aluminum silicate (MAS), on the properties of sodium caseinate (SC) dispersions and films. Moreover, the SC-MAS dispersions were evaluated for film coating of modified-release tablets. The results showed that MAS addition led to particle flocculation and viscosity synergism in the SC-MAS dispersions. Exfoliated or intercalated nanocomposites of the SC-MAS films could be formed because of the molecular interaction of both components via hydrogen bonding. The puncture strength and elongation of the dry SC films decreased with increasing MAS ratios. However, MAS added enhanced the puncture strength of the wet films and reduced drug permeability and diffusivity across the films in acidic medium because of lower water uptake and denser matrix structure of the films. The SC-MAS dispersions showed strong potential for use as a film coating material with few defects in the coated acetaminophen (ACT) tablets. The ACT release of the coated tablets in acidic medium was modified by varying the MAS ratios and film coating levels. In addition, the SC-MAS coated tablets possessed sustained-release behavior for the drug under simulated gastrointestinal conditions. This finding indicates that the SC-MAS nanocomposite films can be applied as a tablet coating material to modify drug release.