Oxidation-stabilized tamper-resistant dosage form

A tamper-resistant pharmaceutical dosage form in form of a tablet having a breaking strength of at least 300 N thermoformed by hot-melt extrusion of a mixture comprising

• a pharmacologically active ingredient (A),
• a free physiologically acceptable multicarboxylic acid (B) in an amount of from 0.001 wt.-% to 5.0 wt.-%, based on the total weight of the pharmaceutical dosage form,
• an antioxidant selected from the group consisting of ascorbic acid or the salts thereof, ascorbylic palmitate, α-tocopherol, vitamin E-succinate, vitamin E-palmitate, butylhydroxyanisol, butylhydroxytoluene, monothioglycerine, coniferyl benzoate, nordihydroguajaretic acid, gallus acid esters, phosphoric acid, and sodium bisulphite;
• in an amount of from 0.001 wt.-% to 5.0 wt.-%, based on the total weight of the pharmaceutical dosage form;
• and
• a polyalkylene oxide (C) having a weight average molecular weight Mw of at least 200,000 g/mol.