Abstract: In this study, emulsion-solvent evaporation method was applied to prepare the cellulose acetate (CA) aqueous dispersion. Upon the analyzing of the character of the aqueous dispersion, a controlled release formulation of salbutamol sulfate coated with cellulose acetate aqueous dispersion was prepared through orthogonal experiment design. The factors that control the drug release character of the tablets were investigated. The drug release mechanism of the formulation was also studied. The experimental results indicated that CA aqueous dispersion had excellent film-forming ability under the effect of plasticizer. The drug release profile of the controlled release tablets coated with CA aqueous dispersion exhibited zero-order release character and the drug release rate was modulated by the osmotic pressure of the dissolution medium.

Key words: Cellulose acetate, Salbutamol sulfate, Osmotic pump, Aqueous dispersion