The Mechanical and Adhesion Properties of Aqueous Based Hydroxypropyl Methylcellulose Coating Systems Containing Polydextrose and Titanium Dioxide

The effect of titanium dioxide and polydextrose on film adhesion to microcrystalline cellulose tablet surface and mechanical properties of aqueous-based hydroxypropyl methylcellulose free films were evaluated using a Lloyd LRX materials testing machine. The free films and the films applied to tablets were prepared by using a pneumatic spraying technique similar to that used in fluidized-bed coaters.The film adhesion was found to increase with increasing concentrations of titanium dioxide and polydextrose in the film. The addition of polydextrose to the film increased only slightly the moisture permeation of coated tablets. This may be due to the hygroscopic nature of polydextrose. Over the range studied, the addition of polydextrose reduced the elongation and the tensile strength of the film, indicating decreased deformation capacity of the film and a risk of cracking.