Preparation and characterization of aqueous vitamin E/Soluplus^® dispersions for film coating applications

The goals of this study were to (1) delineate a technique to prepare stable aqueous vitamin E/Soluplus^® dispersions; (2) characterize films cast from the aqueous dispersions; and (3) demonstrate the utility of the aqueous dispersions in fluid bed coating applications. This study demonstrated the feasibility of using vitamin E in the preparation of amphiphilic film withs potential use in delayed-release coating applications.

Low viscosity aqueous vitamin E/Soluplus^® dispersions were prepared by first spray drying ethanolic vitamin E/Soluplus^® solutions followed by high-shear homogenization of the solid dispersions in water. Concentrated (10%) aqueous dispersions containing 0%, 10%, 20%, and 30% of vitamin E in the binary blend with Soluplus^® were then cast into films and characterized for contact angle and mechanical strength by texture analysis.

All films were hydrophilic and homogenous, which confirmed the utility of vitamin E as a plasticizer for the Soluplus^® polymer. The 0% and 10% films were brittle whereas the 30% were tacky. The 20% dispersion was subsequently used to coat acetaminophen granules by a fluidized bed process to a dry weight gain of 10-30%. When tested by a dissolution study, a delay in acetaminophen release was observed as a function of weight gain.

The results from this study demonstrated that it is feasible to produce stable vitamin E/Soluplus^® aqueous dispersions to be used as solvent-free functional film coating materials.