Products
Methacrylic acid-ethyl acrylate copolymer (1:1) dispersion 30% is available from specialist retailers (brand name: Eudragit). The copolymer is included as an excipient in numerous enteric-coated drugs.
Structure and properties
Methacrylic acid-ethyl acrylate copolymer (1:1) dispersion 30% is an aqueous dispersion of a copolymer of methacrylic acid with ethyl acrylate having an average molecular weight of about 250,000. The ratio of carboxyl groups to ester groups is about 1:1. Suitable surfactants such as sodium dodecyl sulfate or polysorbate 80 may be included. The substance is present as an opaque, white and slightly viscous liquid that is miscible with water. The methacrylic acid-ethyl acrylate copolymer is a white, free-flowing powder that is dispersible in water.
Effects
The dispersion is used for coating oral dosage forms. The coating does not dissolve in the acidic environment of the stomach. Only in the alkaline environment of the intestine are the active ingredients contained released from a pH of about 5.5. The effects are based on the different protonation of the carboxy groups in acidic and basic solutions.
Indications for use
For the preparation of enteric-coated tablets, capsules and granules.
