INTRODUCTION
Ethylcellulose is a widely used film-forming polymer used to impart modified-release characteristics or mask poor-tasting ingredients. Ethylcellulose is broadly accepted due to its outstanding safety profile and ease of use in conventional spray-coating equipment. Film-coating operations with ethylcellulose can be completed using solutions of ethylcellulose in organic solvents or from aqueous dispersions. ETHOCELTM brand ethylcellulose is the oldest trademarked brand available from The Dow Chemical Company and continues to be an exciting source of innovation. Dow’s constant pursuit of production excellence has resulted in an ethylcellulose product that adheres to exceptionally narrow viscosity limits, contains fewer insoluble fibers, and is reproducibly ethoxylated. With the introduction of the new ETHOCEL High Productivity (HP) grade, these advanced features have been further optimized for use in dry powder layering processes using rotor granulation technology.
DRAWBACKS OF TRADITIONAL SYSTEMS
Traditional spray-coating systems of ethylcellulose rely on dissolution of the polymer into a solvent to apply the coating onto the substrate. The film-formation process occurs by atomizing the solution into small droplets that coalesce on the surface of the substrate, allowing the carrier medium to evaporate, leaving an ethylcellulose film on the substrate. This process is repeated hundreds of times during the coating process, resulting in many layers of ethylcellulose that create a solid, homogenous film. This process is well understood and allows for great film formation, providing stable, reproducible coatings.
