There is provided a sustained-release pharmaceutical composition comprising a solid, continuous network comprising an excipient with a high mechanical strength, which network also comprises pores, within which pores is interspersed a mixture of an active ingredient and a film-forming agent, characterized in that said pores are formed during the production of the composition. Compositions of the invention find particularly utility as abuse-resistant formulations comprising opioid analgesics that may be employed in the treatment of chronic pain.