title: Sustained release of ganciclovir from poly(lactide-co-glycolide) microspheres.
abstract: Biodegradable poly(lactide-co-glycolide) microspheres loaded with ganciclovir were produced using the emulsification/solvent evaporation technique. The effects of drug-to-polymer ratio and dispersion time on the drug content in the microspheres were investigated. The release rate of the drug was studied for 20 weeks in a phosphate buffered solution of pH 7 at 37 degrees C. Data revealed that lower drug content was obtained with increasing drug-to-polymer ratio and decreasing dispersion time. The release of the drug followed a triphasic release pattern, i.e. an initial burst, a diffusive phase and a second burst. The initial burst occurred within the first 2 days of immersion. After the burst, the release was by diffusion for up to 13 weeks, followed by another burst release, which signals the onset of bulk degradation of the polymer. Gel permeation chromatography (GPC), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and ultraviolet spectroscopy (UV) were used to follow the hydrolytic degradation and drug release rate of the microspheres.
authors.affiliation: School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore.
authors.forename: X
authors.initials: X
authors.lastname: Chen
authors.forename: C P
authors.initials: CP
authors.lastname: Ooi
authors.forename: W S
authors.initials: WS
authors.lastname: Lye
authors.forename: T H
authors.initials: TH
authors.lastname: Lim
mesh_terms: D000998:Antiviral Agents / Q000008:administration & dosage* / Q000032:analysis; D001673:Biodegradation, Environmental; D002152:Calorimetry, Differential Scanning; D002850:Chromatography, Gel; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D016503:Drug Delivery Systems; D015774:Ganciclovir / Q000008:administration & dosage* / Q000032:analysis; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D008970:Molecular Weight; D011098:Polyglactin 910 / Q000737:chemistry*
chemical_list: D000998:Antiviral Agents; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D011098:Polyglactin 910; D015774:Ganciclovir