In pharmaceutical drug delivery of solid oral dosage forms film coatings are frequently applied. The motivation for coating dosage forms range from cosmetic considerations (colour, gloss), improving the stability (light protection, moisture and gas barrier) and making it easier to swallow the tablet. In addition, functional coatings can be used to modify the drug release behaviour from the dosage form. Depending on the polymers used it is possible either delay the release of the drug (such as in enteric coatings) or use the coating to sustain the release of the drug from the dosage form over extended periods of time.
A film coating is a thin polymer-based coat applied to a solid dosage form such as a tablet. The thickness of such a coating is usually between 20-100 µm. It is possible to follow the dynamic curing effect on tablet coating structure by using non-destructive analytical methodologies.
Film coating formulations usually contain the following components:
- Polymer
- Plasticizer
- Colourant
- Opacifier
- Solvent
- Vehicle
Functionality wise it is further divided into:
- Immediate release coating
- Sustained release or modified release coating
- Enteric release coating
Video Film coating
References
Source of article : Wikipedia
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