Disclosed is a solid oral extended release pharmaceutical dosage form comprising a multi-layered extended release matrix formulation with sandwich-type or half sandwich-type structure, the extended release matrix formulation comprising (1) a first composition forming an active agent-containing first layer of the extended release matrix formulation comprising: (a) at least one polyethylene oxide having, based on rheological measurements, an approximate molecular weight of at least 1000000； and (b) at least one active agent (preferably selected from the opioid analgesics hydromorphone hydrochloride or hydrocodone bitartrate)； and (2) a second composition forming an active agent-free second layer of the extended release matrix formulation comprising at least one polyethylene oxide, and wherein the extended release matrix formulation preferably has a cracking force of at least about 120 N, and/or a &ldquo；penetration depth to crack&rdquo； distance of at least about 1.4 mm. Also disclosed is a process of preparing a solid oral extended release pharmaceutical dosage form as defined above, comprising at least the steps of: (a) combining (1) at least one active agent, and (2) at least one polyethylene oxide having, based on rheological measurements, an approximate molecular weight of at least 1,000,000, to yield a first composition for an active agent-containing layer first layer； (b) providing a second composition comprising at least one polyethylene oxide having, based on rheological measurements, an approximate molecular weight of at least 1,000,000 or of less than 1,000,000, to yield a second composition for an active agent-free layer second layer, (c) shaping the compositions form (a) and (b) to form at least a bilayer extended release matrix formulation； and (d) curing said extended release matrix formulation comprising at least a curing step at a temperature which is at least the softening temperature of said at least one polyethylene oxide.
