The invention provides a tamper-resistant dosage form including a therapeutic agent-substrate complex embedded in a thermo-formable matrix; such that the complex includes at least one therapeutic agent bound to at least one substrate to form the therapeutic agent-substrate complex. The at least one substrate is being selected from the group consisting of a polyelectrolyte, an organic counter-ion, a pharmacologically inert organic component of a prodrug, an inclusion compound and an inorganic adsorbent; and the thermo-formable matrix includes one or more thermoplastic polymers and optionally at least one pharmaceutical additive.