Article | January 16, 2009

Organoleptically Appealing Immediate Release EUDRAGIT® Coatings

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Poster: Organoleptically Appealing Immediate Release EUDRAGIT® Coatings

By Evonik Röhm GmbH

Pharmaceutical tablet formulations are coated, either to have a functional film or a regular film over the core surface. The regular film coating renders, improved visual appearance, ease of swallow ability and increases palatability by masking unpleasant taste and objectionable odors of the drug. The addition of color to the film helps creating distinctive tablet characteristics, increases brand recognition and creation of an ideal surface, for the application of high clarity printing1. Universally hydroxypropyl methylcellulose (HPMC) is being used as the film former due to its inertness towards the release of the drug.

The cationic ammonioalkyl methacrylate copolymer (EUDRAGIT® RL 30 D)2 being pH-independent & water-insoluble but swellable polymer, finds application in sustained release formulations. The films produced, swell & the drug is released through diffusion resulting in the sustained release effect. However the incorporation of a hydrophilic swellable polymer, sodium carboxymethyl cellulose in these films, helps in making the film disintegrating, thus forming immediate release EUDRAGIT® films. The dissolution of films prepared using the above combination, is by complete film disintegration, whereas coatings of hydroxypropyl methyl cellulose dissolve by erosion.

EUDRAGIT® RL 30 D is a cationic ammonioalkyl methacrylate copolymer. It is a pH-independent & water-insoluble but swellable polymer. During the coating process the polymer is deposited as compact & smooth layers onto the substrate surface. Since the film produced is uninterrupted & the polymer per se is water insoluble but swellable, after the film comes in contact with a solvent, it starts swelling. The drug from the core can escape out, only through diffusion through the swollen but intact film. Sodium carboxy methylcellulose, a hydrophilic swellable polymer when added to the ammonioalkyl methacrylate copolymer, causes an interruption of the continuous film. When this film comes in contact with a solvent, due to the interruption of the film with the sodium carboxy methylcellulose the film disintegrates. This ensures a quick & complete release of the drug from the film.

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Poster: Organoleptically Appealing Immediate Release EUDRAGIT® Coatings