| abstract |
A controlled-release solid oral dosage form comprising a plurality of inert pharmaceutical beads coated with an analgesically effective amount of an opioid analgesic or a mixture of opioid analgesics, or salts thereof, wherein the inert pharmaceutical beads are covered with a release controlling coating, in vitro USP stirrer method at 100 rpm. in 900 ml of an aqueous buffer, pH 1.6 and 7.2, at 37 ° C, is from 12.5% to 42.5% by weight. % of opioid released after 1 h, from 25% to 65% by weight % of opioid released after 2 h, from 45% to 85% by weight % opioid released after 4 h and more than 60 wt. of the opioid released after 8 hours, wherein the in vitro release rate is essentially pH independent, wherein the difference, at any time, between the amount of opioid released at one pH and the amount released at any other pH when measured in vitro using the USP stirrer method at 100 rpm. in 900 ml of an aqueous buffer, not more than 10% by weight, and said in vitro release rate is selected such that the maximum plasma level of said opioid is in vivo from 2 to 8 hours after administration of the dosage form, said dosage form the form provides an extended duration of therapeutic effect of about 24 hours |