Immediate release tablet cores of insoluble drugs having sustained-release coating

A sustained release tablet for oral administration, comprising

• an immediate release tablet core including an insoluble therapeutically active agent having an aqueous solubility of less than or equal to about 5 mg/ml, said tablet core containing a sufficient amount of said therapeutically active drug to render a therapeutic effect, said tablet core coated with a sustained release film coating comprising a hydrophobic material permitting a 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 about 1.6 and about 7.2, at 37° C. between 12.5 and 42.5% (by wt) released after 1 hour, between 25 and 56% (by wt) released after 2 hours, between 45 and 75% (by wt) released after 4 hours and between 55 and 85% (by wt) released after 6 hours.

A method for preparing a oral sustained release formulation of an insoluble therapeutically active agent, comprising

• coating an immediate release tablet core including an insoluble therapeutically active agent in an amount sufficient to render a therapeutic effect, the insoluble therapeutically active agent having an aqueous solubility of less than or equal to about 5 mg/ml, with a controlled release coating of a hydrophobic material such that said formulation reproducibly releases said insoluble therapeutically active agent at a desired rate over an extended period of time when exposed to an aqueous solutions.

A method of treating a patient with a dose of a pharmaceutical formulation containing an insoluble therapeutically active agent over an extended period of time, comprising

• preparing an immediate release solid tablet core comprising a therapeutically active agent in an amount sufficient to render a therapeutic effect, the therapeutically active agent having a solubility of less than or equal to about 5 mg/ml;
• coating said tablet core with a hydrophobic material such that said formulation reproducibly releases said insoluble therapeutically active agent at a dissolution rate between 12.5% and 42.5% (by wt) released after 1 hour, between 25% and 55% (by wt) released after 2 hours, between 45% and 75% (by wt) released after 4 hours and between 55% and 85% (by wt) after 6 hours when measured by the USP Paddle Method at 100 rpm at 900 ml aqueous buffer (pH between 1.6 and 7.2) at 37° C.

A sustained release tablet for oral administration, comprising

• an immediate release tablet core including from about 300 mg to about 500 mg acetaminophen, and a therapeutically effective amount of an analgesic agent selected from the group consisting of hydromorphone, oxycodone, dihydrocodeine, codeine, dihydromorphine, morphine, buprenorphine, salts of any of the foregoing, and mixtures of any of the foregoing, said immediate release tablet core providing the dissolution of not less than 75% of the acetaminophen in 45 minutes when said tablet core is placed in 900 ml 0.1 N hydrochloric acid, said tablet core being coated with a sufficient amount of a hydrophobic material such that said acetaminophen and said analgesic agent are released from the coated tablet over an extended period of time of at least about 12 hours.