Cellulose acetate phthalate

Cellulose acetate phthalate (CAS 9004-38-0), commonly abbreviated as CAP, is a cellulose-derived polymer ester used primarily as an enteric coating agent in pharmaceutical manufacturing.

It controls the release profile of oral dosage forms by remaining intact in gastric acid while dissolving in the higher pH environment of the intestine. CAP is the material of choice for enteric coating tablets.

It is used for capsules and granules where protection from stomach acid is required, particularly for acid-sensitive active pharmaceutical ingredients. It is also used in sustained-release pellet systems.

In these systems, coating thickness and polymer concentration determine the dissolution lag time. Formulators incorporate CAP into film-coating solutions alongside plasticizers to achieve consistent coating uniformity.

This process is essential at commercial batch scale. Beyond solid dosage forms, it functions as a binder and matrix former in controlled-release granulation processes for various pharmaceutical applications.

Cellulose acetate phthalate is supplied as a white to off-white powder. It is available in pharmaceutical-grade specifications meeting USP and Ph. Eur. standards for global compliance.

These are the primary grades demanded by regulated drug manufacturers. Suppliers typically offer it in fiber drum or multi-wall bag packaging suited to GMP production environments and large scale logistics.