cellulose acetate phthalate

Cellulose acetate phthalate (CAP) is a cellulose ester polymer created by acetylation and phthalation of cellulose, combining properties of both ester groups to achieve specific solubility and thermal behavior. It is primarily used in pharmaceutical applications as an enteric coating material for oral tablets and capsules, where it selectively dissolves in the intestine rather than the stomach, protecting active ingredients and enabling targeted drug delivery. CAP is valued in this role for its biocompatibility, film-forming ability, and pH-dependent dissolution profile, making it a preferred choice over some alternative polymers where controlled-release performance and regulatory acceptance are critical.