title: An investigation into the release of cefuroxime axetil from taste-masked stearic acid microspheres. Part 1: the influence of the dissolution medium on the drug release profile and the physical integrity of the microspheres.
abstract: The dissolution properties of stearic acid-coated cefuroxime axetil (SACA) systems have been studied with a view to investigating the effects of the dissolution medium on both the release rate and the physical integrity of the microspheres. The release from the spheres was found to be highly dependent on the media used, with systems in distilled water (pH 6.8) and pH 5.9 Sorensens modified buffer showing a relatively slow release which exhibited linearity with the square root of time, implying a diffusion process. The rate of release from systems in pH 7.0 and 8.0 buffer was considerably faster and did not follow simple diffusion kinetics. Examination of the microspheres after immersion in the various media indicated a change in the integrity of the spheres in those media which showed the most rapid release. This was particularly marked when the systems were dried in buffer, with disintegration seen in the higher pH systems. It is suggested that the release of the drug is dependent both on diffusion through the intact microspheres and changes in the physical integrity of the spheres as a result of a reaction with the surrounding medium.
authors.affiliation: Centre for Materials Science, The School of Pharmacy, 29-39 Brunswick Square, London, UK.
authors.forename: H J
authors.initials: HJ
authors.lastname: Robson
authors.forename: D Q
authors.initials: DQ
authors.lastname: Craig
authors.forename: D
authors.initials: D
authors.lastname: Deutsch
mesh_terms: D002444:Cefuroxime / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000737:chemistry; D002511:Cephalosporins / Q000008:administration & dosage* / Q000737:chemistry*; D005079:Excipients; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D011355:Prodrugs / Q000008:administration & dosage* / Q000737:chemistry*; D012995:Solubility; D013229:Stearic Acids; D013649:Taste
chemical_list: D002511:Cephalosporins; D005079:Excipients; D011355:Prodrugs; D013229:Stearic Acids; D002444:Cefuroxime; C040738:cefuroxime axetil