Tamper resistant and dose-dumping resistant pharmaceutical dosage form

A process for the production of a tamper-resistant pharmaceutical dosage form comprising a pharmacologically active ingredient embedded in a prolonged release matrix, which comprises a prolonged release matrix material selected from the group consisting of nonionic acrylic polymers and waxy materials and which provides prolonged release of the pharmacologically active ingredient, wherein the prolonged release matrix material is employed in the form of an aqueous dispersion, said process comprising extruding a mixture comprising the pharmacologically active ingredient and the prolonged release matrix material in the presence of water, and evaporating the water from the extruded material in the course of the extrusion process.