Alkyl-substituted cellulose-based sustained-release oral drug dosage forms

A sustained release oral drug dosage form for releasing a solution of a drug into the stomach comprising a plurality of solid particles of initially about 3-9 mm in diameter in maximum dimension, each particle containing a solid-state drug dispersed within a non-chemically crosslinked alkyl-substituted cellulose selected from the group consisting of hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, carboxymethylcellulose, and hydroxymethylcellulose, in a weight ratio of drug to polymer of about 1:9 to 9:1, the particles (i) swelling unrestrained dimensionally up to about three times their original diameter via imbibition of water from gastric fluid to increase the size of the particles to promote retention within the stomach, and make the particles slippery, which also promotes their retention within the stomach, (ii) permitting dissolution of the dispersed drug by imbibed gastric water while the drug is within the particle and release of the resulting solution, thus assuring that only drug in solution contacts the gastric mucosa, (iii) protecting undissolved drug from stomach enzymes or pH and duodenum, and (iv) maintaining their physical integrity over at least a substantial portion of the time period during which the drug is released into the stomach and then dissolves;

• and wherein the dosage form is in the form of a tablet or capsule that maintains the particles in a packed mass prior to their ingestion and then rapidly disintegrates in the gastric fluid to permit the particles to disperse in the stomach.