Drug release from compressed hydrophilic POLYOX-WSR tablets.

Drug release from compressed tablets manufactured with a powder mixture of poly(ethylene oxide) (PEO), a drug, and magnesium stearate is presented. Several factors such as molecular weight, drug loading, drug solubility, the pH of the dissolution medium, and stirring rate are investigated. The drug release from the high molecular weight PEO tablets (MW = 2 x 10(6) and 4 x 10(6)) is governed by the swelling of the polymer rather than by the erosion of the polymer, leading to anomalous release kinetics. However, the drug release from the low molecular weight PEO (MW = 0.9 x 10(6)) is controlled primarily by the swelling/erosion of the polymer, resulting in front synchronization and a constant release rate. It is observed that drug loading and drug solubility do not influence the release of drugs from low molecular weight PEO tablets. The pH of the dissolution medium and the stirring rate do not affect the drug release regardless of the molecular weight of the PEO.