If a tablet is described as having an 'enteric coating' (e/c) or 'gastro-resistant', it means that there is a coating which is designed to hold the tablet together when in the stomach. This clever science relies on the fact that the stomach is acid and the intestines, where food goes after the stomach, are not. The coating is designed to hold together in acid conditions and break down in non-acid conditions and therefore release the drug in the intestines.
There are three reasons for putting such a coating on a tablet or capsule ingredient:
- To protect the stomach from the drug
- To protect the drug from the stomach
- To release the drug after the stomach e.g. in the intestines
The drugs which most commonly cause stomach ulcers like aspirin, diclofenac and naproxen are frequently available with enteric coatings. Omeprazole, which is a drug which stops the stomach from producing acid, is itself broken down in acid and therefore the drug generally has an enteric coating around it either as a granule in the capsules or as a granule in the dispersible form. Sulfasalazine is used either for the treatment of arthritis or for the treatment of Crohn's disease which is inflammation of the intestines. When used for arthritis, it is very often given without an enteric coating so that it can be absorbed more quickly. For Crohn's, it is needed to work in the intestines so it is given an enteric coating.
It can be seen that an enteric coating has advantages and therefore such tablets or the contents of enteric coated capsules should never be crushed before being taken.