COLONIC-TARGETED ORAL DRUG-DOSAGE FORMS BASED ON CROSSLINKED HYDROGELS CONTAINING AZOBONDS AND EXHIBITING pH-DEPENDENT SWELLING

摘要

The invention relates to dosage forms of drugs administered orally and to be released in the colon, comprising a drug enclosed in a crosslinked hydrogel having a swelling pH dependent and which is composed of a comonomer such as ionizable acrylic acid, a non-ionizable comonomer such as an acrylamide, and a crosslinking agent which contains an aromatic azo bond. Selectively releasing the drug in the colon is achieved through the combination of the swelling properties depending on the pH suitable for the hydrogel and degradation properties of said hydrogel by enzymatic splitting of the azo bonds made by the azoreductases.