CONTROLLED RELEASE DIHYDROCODEINE COMPOSITION

摘要

A solid controlled release, oral dosage form, the dosage form comprising an analgesically effective amount of dihydrocodeine or a salt thereof in a controlled release matrix wherein the dissolution rate in vitro of the dosage form, when measured by the USP Paddle Method at 100 rpm in 900 ml aqueous buffer (pH between 1.6 and 7.2) at 37.degree.C is between 25% and 60% (by weight) dihydrocodeine released after 1 hour, between 45% and 80% (by weight) dihydrocodeine released after 2 hours, between 60% and 90% (by weight) dihydrocodeine released after 3 hours and between 70% and 100% (by weight) dihydrocodeine released after 4 hours, the in vitro release rate being independent of pH between pH 1.6 and 7.2 and chosen such that the peak plasma level of dihydrocodeine obtained in vivo occurs between 2 and 4 hours after administration of the dosage form.