Mucoadhesive pharmaceutical composition for the controlled release of active principles

A mucoadhesive pharmaceutical composition for the controlled release of active pharmaceutical principles in the buccal cavity or through a mucus membrane, which is a solid matrix in which an active pharmaceutical principle is homogeneously dispersed, wherein the mucoadhesion and the controlled release are provided by between 5 and 85% of the total mass of said matrix of a compound (A) consisting of one or a number of vinyl acetate/polyvinylpyrrolidone copolymers, said matrix being in the form of a preformed film having a thickness between 0.2 and 3.0 millimeters and having a surface area between 0.1 and 5.0 square centimeters.