C-A-P or cellulose acetate phthalate is a pH sensitive cellulose derivative designed for enteric coating of solid dosage forms. C-A-P enteric coating material withstands prolonged contact with acidic gastric fluids, but dissolves readily in the mildly acidic to neutral environment of the small intestine.

C-A-P is compatible with many plasticizers and used in combination with other coating agents for controlled-release preparations.