MATRIX TYPE TABLET FORMULATION FOR CONTROLLED-RELEASE OF HIGHLY WATER-SOLUBLE DRUGS

Matrix type formulations with dicalcium phosphate dihydrate (DCPD) usi ng a polymeric binder (Eudragit RSPM(R)) to obtain controlled release of highly water soluble drugs has been investigated. The drug, DCPD an d Eudragit RSPM(R) were granulated using isopropyl alcohol with and wi thout a plasticizer (Diethyl phthalate, DEP). Addition of Eudragit did not appear to affect the release profile. However, addition of a plas ticizer had a significant effect on the rate of release. The release a ppears to follow first order kinetics and the rate constant decreased linearly with increasing DEP concentration. A directly compressible mi xture was also formulated by coating DCPD particles with DEP with and without Eudragit RSPM(R).