IN-VITRO EVALUATION OF SUSTAINED-RELEASE MATRIX TABLETS PREPARED WITHNEW MODIFIED POLYMERIC CARBOHYDRATES

The study of the rheological and compressional properties of sustained -release matrix tablets prepared with new polymers obtained by graft c opolymerization of methyl methacrylate (MMA) on various carbohydrates is the main purpose of this work. All the mixtures had good flow prope rties, showing cellulose derivatives mixtures the best values. Powders without homopolymers showed a statistically significant lower flow ra te than mixtures with homopolymers. All the mixtures with hydroxypropy l starch polymers showed better statistically significant compactibili ty and plasticity than the hydroxypropyl cellulose derivatives. Practi cally all the mixtures accomplished with the requirements of direct co mpression excipients in relation with lubrication coefficient. All the tablets elaborated with mixtures with homopolymers required a total w ork lower than the mixtures without homopolymers. Tablets from all pro ducts passed the test for weight uniformity, except the tablets of car boxymethyl starch (CS-MMA) without homopolymer. Only hydroxypropylcell ulose tablets demonstrated an acceptable friability. Only standard tab lets and CS-MMA without homopolymers exhibited disintegration times hi gher than 30 min. A clearly different behaviour between the new polyme rs and the standards was observed in relation with dissolution test.