DRUG-RELEASE FROM A NEW FAMILY OF GRAFT-COPOLYMERS OF METHYL-METHACRYLATE .1.

Hydrophilic matrices are an interesting option when developing an oral drug release device. In this work we have produced hydrophilic matric es tablets by direct compression. Previously graft copolymers were syn thesized as an important component of the tablets: hydroxypropyl starc h-methyl methacrylate (HS-MMA), carboxymethyl starch-MMA (CS-MMA) and hydroxypropyl cellulose-MMA (HC-MMA). The polymeric component was mixe d with Emcompress(R), stearic acid and theophylline. All the products fulfilled the requirements for good flow according to literature. L-fo rmulations show lower values of plasticity than O-formulations. Howeve r, L-formulations exhibit higher compactibility values than O-formulat ions. In general, all the formulations with O-polymers show faster rel ease of the drug at three pHs used. On the other hand, these tablets h ave the capacity to hydrate quickly forming a gelatinous layer, so it is necessary to achieve controlled drug release from hydrophilic matri ces. In relation with the dissolution efficiency over 8 h, formulation s with HS-MMAL and NaCMC show very similar results, although the relea se of theophylline from NaCMC tablets at different pHs was always slig htly slower than HS-MMAL tablets. (C) 1997 Elsevier Science B.V.