CELLULOSE POLYMERS FOR THE CONSTANT RELEASE OF A WATER-INSOLUBLE BENZODIAZEPINE

The realization of programmable constant release oral dosage forms des igned for the extended release of a water-insoluble benzodiazepine (di azepam), is described. The dosage forms are constituted by hydrophilic matrix tablets which are obtained by direct compression of the drug w ith two different kinds of cellulose ethers: a water swellable polymer (cross-linked sodium carboxymethylcellulose), which acts as dissoluti on rate enhancer of the drug, and a water gelling polymer (hydroxyprop ylmethyl cellulose). In vitro tests showed that the presence of the en hancer leads to a remarkable improvement in the dissolution behaviour of the benzodiazepine. The matrices, after the contact with the dissol ution medium, are subject to both gelation and erosion processes and t hey appear to be capable of releasing the drug at a nearly constant ra te until almost the entire drug content is released.