Review on enteric coated polymers

Enteric coated tablets are solid unit dosage forms which are designed to bypass the stomach and release the drug in intestine and are meant for oral administration. The word “enteric” indicates small intestine; therefore, enteric coatings prevent release of medication before it reaches the tiny intestine. Most enteric coatings work by presenting a coated surface that's stable at the highly acidic pH found within the stomach, but breaks down rapidly at a less acidic (relatively more basic) pH. Materials used for enteric coatings include CAP, CAT, PVAP and HPMCP, fatty acids, waxes, shellac, plastics and plant fibers. The present review describes enteric coating, their ideal properties, benefits and limitation, various polymers used, their chemical structure, criteria for drug selection and mechanism, methods of producing and evaluation of enteric coated tablets. Recently, these have attracted the interest of many formulators due to their advantages over the conventional drug delivery systems as they prolong the dosing intervals and also increase patient compliance.