Encased tamper resistant controlled release dosage forms

In certain embodiments, the present invention relates to a solid controlled release dosage form comprising: a core comprising a first portion of an opioid analgesic dispersed in a first matrix material, and a cover enclosing the core and comprising A second portion of the opioid analgesic dispersed in a second matrix material; Wherein the amount of active agent released from the dosage form is proportional within 20% at the time elapsed from 8 to 24 hours, as measured by an in vitro dissolution in an apparatus USP 1 (basket) at 100 rpm in 900 ml Of simulated gastric fluid without enzymes (SGF) at 37 ° C.