Multi-Layer Tablets and Bioadhesive Dosage Forms

Bioadhesives coatings increase the gastrointestinal retention time of orally-ingested medicaments. Certain bioadhesive coatings producing a fracture strength of at least 100 N/m2, as measured on rat intestine, when applied to at least one surface of a pharmaceutical dosage form for oral delivery of a drug, result in a gastrointestinal retention time of at least 4 hours in a fed beagle dog model, during which the drug is released from the dosage form. Multi-layer tablets, particularly those including hydrophobic excipients, are useful in administering hygroscopic and/or deliquescent drugs. In addition, varying the amount of drug in multi-layer tablets allows the release rate of the drug to be controlled.