CONTRIBUTION TO THE STUDY OF NEW GRAFT COPOLYMER MATRICES FOR DRUG-DELIVERY SYSTEMS - TECHNOLOGICAL STUDY

Cellulose and starch derivatives have long been used for their ability to sustain the release of drugs. The use of polymer mixtures represen ts a potential way of achieving the required release properties. It is known that the release of a drug from a matrix system is produced by diffusion through the gel formed. The aim of this work is focused on t he study of viscosity, flowability and compactibility values of polyme rs for drug delivery matrices. Previously synthesized graft copolymers were used: hydroxypropyl starch-methyl methacrylate (HS-MMA), carboxy methyl starch-MMA (CS-MMA) and hydroxypropyl cellulose-MMA (HC-MMA). I t is known that polymers with the highest swelling capacity give highe st viscosity value. HC-MMA and CS-MMA graft copolymers can be consider ed pseudogels because through mechanical-dynamical analysis, an inters ection point between the storage modulus and the loss modulus can be s een. All the polymers fulfilled in general the requirements for good f low which will predict a good die filling during the tableting. Howeve r, L-products have the higher values for the compactibility and lubric ation coefficient and the lower values for ejection and maximum upper force. Also, from the study of gel formation done with these products, we can state that L-products will probably lead to more interesting e xcipients to the obtaining of control release matrices. (C) 1997 Elsev ier Science B.V.