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Effect of Ganciclovir on the Hydrolytic Degradation of Poly(lactide-co-glycolide) MicrospheresDivision of Bioengineering, School of Chemical and Biomedical Engineering, Nanyang Technological University, 639798 Singapore
Division of Bioengineering, School of Chemical and Biomedical Engineering, Nanyang Technological University, 639798 Singapore, ascpooi{at}ntu.edu.sg
Department of Ophthalmology, Tan Tock Seng Hospital, 308433 Singapore Ganciclovir (GCV)-loaded poly(lactide-co-glycolide) (PLGA) microspheres, 125 ± 11 µm in diameter, are produced using the emulsification/solvent evaporation technique. The release rate of the drug is studied for 20 weeks in a phosphate-buffered solution of pH 7 at 37°C. The release of the drug shows a triphasic release pattern, i.e., an initial burst, a diffusive phase, and a second burst. The initial burst occurs within the first 2 days of immersion. After the burst, the release is by diffusion for up to 13 weeks, followed by another burst release, which signals the onset of bulk degradation of the PLGA polymer. The presence of GCV molecules decreases the hydrolytic rate of PLGA degradation. Gel permeation chromatography (GPC), differential scanning calorimetry (DSC), field emission scanning electron microscopy (FESEM), and ultraviolet (UV) spectroscopy are used to assess the hydrolytic degradation and drug release rate of the microspheres.
Key Words: poly(lactide-co-glycolide) ganciclovir microspheres triphasic release hydrolytic degradation
Journal of Biomaterials Applications, Vol. 20, No. 3,
287-302 (2006) |
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