Water-insoluble matrix tablets based on oxycodone or one of its pharmaceutically acceptable salts, which can release oxycodone in the body for a long time and that comprise oxycodone inside a compression matrix, said matrix being constituted by a mixture of microcrystalline cellulose and by [poly (vinyl acetate) / polyvinylpyrrolidone (80:20)], said compression matrix further comprising an agent that increases the viscosity that allows the formation of a gel when the tablet is dissolved in a minimum water, characterized in that: - oxycodone or a pharmaceutically acceptable salt thereof represents 10 to 50% by weight of the total weight of the tablet, - said compression matrix represents 50 to 98% by weight of the total weight of said tablet. compressed, advantageously from 85 to 95%, - said mixture of microcrystalline cellulose and [polyvinyl acetate / polyvinylpyrrolidone (80:20)] represents 40 to 100%, advantageously from 50 to 90% by weight of the total weight of the die, and - are obtained by applying compression forces between 10 kN and 160 kN.Comprimidos matriciales insolubles en agua a base de oxicodona o de una de sus sales farmacéuticamente aceptables, que pueden liberar la oxicodona en el organismo de manera prolongada en el tiempo y que comprenden la oxicodona en el interior de una matriz de compresión, estando dicha matriz constituida por una mezcla de celulosa microcristalina y por [poli(acetato de vinilo)/polivinilpirrolidona (80:20)], comprendiendo además dicha matriz de compresión un agente que aumenta la viscosidad que permite la formación de un gel cuando se disuelve el comprimido en un mínimo de agua, caracterizados por que: - la oxicodona o una de sus sales farmacéuticamente aceptables representa del 10 al 50% en peso del peso total del comprimido, - dicha matriz de compresión representa del 50 al 98% en peso del peso total de dicho comprimido, ventajosamente del 85 al 95%, - dicha mezcla de celulosa microcristalina y de [poli(acetato de vinilo)/
