Pharmaceutical formulations containing opioid agonist, opioid antagonist and gelling agent

A controlled release oral dosage form comprising:

• a therapeutically effective amount of an opioid analgesic,
• an opioid antagonist,
• one or more pharmaceutically acceptable excipients, and
• particles of a gelling agent in a substantially non-releasable form, the particles consisting of the gelling agent and one or more pharmaceutically acceptable hydrophobic material(s) and one or more additional pharmaceutically acceptable excipient(s), wherein the gelling agent is coated with a coating or dispersed in a matrix consisting of effective amounts of the one or more pharmaceutically acceptable hydrophobic materials(s) and one or more additional pharmaceutically acceptable excipient(s) to sequester the gelling agent such that the gelling agent is not substantially released from the dosage form which is administered intact, but is released from the dosage form which is crushed in an effective amount to impart a viscosity of at least about 10 cP to a solubilized mixture formed when the crushed dosage form is mixed with from about 0.5 to about 10 ml of an aqueous liquid and which renders the solubilized mixture unsuitable for administration by a route selected from the group consisting of parenteral and nasal administration,
• wherein the one or more pharmaceutically acceptable hydrophobic material(s) are selected from the group consisting of cellulose polymers, acrylic polymers, polylactic acid, polyglycolic acid and a co-polymer of the polylactic acid and polyglycolic acid, and
• said intact dosage form provides pain relief for at least about 12 hours when orally administered to a human patient.

A method of preventing abuse of an oral controlled release dosage form of an opioid analgesic comprising:

• preparing a dosage form with an analgesically effective amount of the opioid analgesic, an opioid antagonist, one or more pharmaceutically acceptable excipients, and particles consisting of a gelling agent and effective amounts of one or more pharmaceutically acceptable hydrophobic material(s) and one or more additional pharmaceutically acceptable excipient(s) to sequester the gelling agent such that the gelling agent is not substantially released from the dosage form which is administered intact, but is released from the dosage form which is crushed in an effective amount to impart a viscosity of at least about 10 cP to a solubilized mixture formed when the crushed dosage form is mixed with from about 0.5 to about 10 ml of an aqueous liquid and which renders the solubilized mixture unsuitable for administration by a route selected from the group consisting of parenteral and nasal administration, wherein the gelling agent is coated with a coating or dispersed in a matrix consisting of said effective amounts of one or more pharmaceutically acceptably hydrophobic material(s) and additional excipient(s), wherein
• the one or more pharmaceutically acceptable hydrophobic material(s) are selected from the group consisting of cellulose polymers, acrylic polymers, polylactic acid, polyglycolic acid and a co-polymer of the polylactic acid and polyglycolic acid,
• said intact dosage form providing effective pain relief for at least about 12 hours when orally administered to a human patient.