Method of preparing controlled long-acting pharmaceutical formulations in unit dosage form having uniform and comparable bioavailability characteristics

Claim 1

A multiplicity of uniform batches of unit doses of a controlled, long-acting release pharmaceutical formulation, in oral tablet form, wherein each of said doses contains active therapeutic agent and a carrier base material, and wherein each of said unit doses has uniform bioavailability from batch to batch, said unit doses being prepared by a method comprising the steps of: (a) adding a quantity of solid, particulate carrier base material consisting essentially of at least one cellulosic ether selected from the group consisting of hydroxypropyl methylcellulose, hydroxypropyl cellulose, carboxymethyl cellulose and ethyl cellulose, to a quantity of a therapeutically active pharmaceutical agent in granular or powder form; (b) mechanically mixing the carrier base material and the therapeutically active agent to form a uniform mixture; (c) discontinuing the mixing and permitting the mixture formed in step (a) to stand for a period of time from 2-27 hours to cause the therapeutically active pharmaceutical agent to become bonded to the carrier base material; and (d) compressing portions of the mixture formed in steps (b) and (c) into solid oral tablet doses, wherein release of said therapeutic agent from a unit dose of a given batch is substantially the same as release of said therapeutic agent from a unit dose of another batch.