Effect of surface roughness and coating solvent on film adhesion to tablets

The adhesion of a polymer film to selected tablet substrates was studied. The effect of tablet surface roughness and film-coating solvent on the adhesion of the film to the tablet was determined. A film-coating solvent having a solubility parameter close to that of the polymer was found to produce a stronger adhesional bond than a solvent having a lower surface tension. An increase in tablet surface roughness also increased film adhesion to the tablet. The adhesion was measured as the force required to peel a section of film from the tablet with a stress-strain analyzer.