| abstract |
A solid dosage form, such as a capsule or tablet, containing a pharmacologically active agent is coated with an anionic polymer which is insoluble in gastric juice and intestinal juice below pH (7) but which is soluble in the intestinal juice of the colon, in an amount sufficient to allow the oral dosage form to remain intact until it reaches the colon. The preferred anionic polymer is a polymer of methacrylic acid partially esterified with methyl in which the ratio between free carboxylic groups and ester groups is about 1: 2. The invention finds particular application in dosage forms of prednisolone and its salts, indomethacin, ibuprofen, and in particular 5-aminosalicylic acid. |