Multiple-matrix monolithic moulded part for the diffusion of active ingredients and method for obtaining same

A monolithic molded part comprised of multiple cohesive matrices, having a non-concentric continuous structure, made up of the combination of two to four simple matrices, welded together and obtained by multi-shot molding, wherein each of said simple matrices is made of thermoplastic polymer and contains a homogeneous mixture of at least one active ingredient and a solvent, said at least one active ingredient being different from another active ingredient contained in a neighboring simple matrix, each of said active ingredient having its own release kinetics, and wherein all of said active ingredients are released simultaneously at substantially different or substantially similar speeds, so that the sum of the quantities of active ingredients released makes it possible to achieve the desired beneficial effects by synergy, wherein said neighboring simple matrices are welded together, side by side or face to face, so that the weld ensures the structural continuity of the monolithic molded part, and wherein said weld, which constitutes the interface between neighboring matrices, consists of the mixture, in molten state, of said thermoplastic polymer forming said matrices, wherein said structural continuity is adapted to the migration of said solvent for said at least one active ingredient from one simple matrix to another, wherein the quantity of solvent is different in each of the simple matrices.