Publication: Effect of poly(lactide-co-glycolide) molecular weight on the release of dexamethasone sodium phosphate from microparticles
Issued Date
2007-04-03
Resource Type
ISSN
14645246
02652048
02652048
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2-s2.0-33947622085
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Mahidol University
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SCOPUS
Bibliographic Citation
Journal of Microencapsulation. Vol.24, No.2 (2007), 117-128
Suggested Citation
Saowanee Jaraswekin, Sompol Prakongpan, Roland Bodmeier Effect of poly(lactide-co-glycolide) molecular weight on the release of dexamethasone sodium phosphate from microparticles. Journal of Microencapsulation. Vol.24, No.2 (2007), 117-128. doi:10.1080/02652040701233655 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/24318
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Title
Effect of poly(lactide-co-glycolide) molecular weight on the release of dexamethasone sodium phosphate from microparticles
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Abstract
The objective of this study was to investigate the effect of poly(lactide-co-glycolide) (PLGA) molecular weight (Resomer® RG 502H, RG 503H, and RG 504H) on the release behavior of dexamethasone sodium phosphate-loaded microparticles. The microparticles were prepared by three modifications of the solvent evaporation method (O/W-cosolvent, O/W-dispersion, and W/O/W-methods). The encapsulation efficiency of microparticles prepared by the cosolvent- and W/O/W-methods increased from ∼50% to >90% upon addition of NaCl to the external aqueous phase, while the dispersion method resulted in lower encapsulation efficiencies. The release of dexamethasone sodium phosphate from PLGA microparticles (>50 μm) was biphasic. The initial burst release correlated well with the porosity of the microparticles, both of which increased with increasing polymer molecular weight (RG 504H > 503H > 502H). The burst was also dependent on the method of preparation and was in the order of dispersion method > WOW method > consolvent method. In contrast to the higher molecular weight PLGA microparticles, the release from RG 502H microparticles prepared by cosolvent method was not affected by volume of organic solvent (1.5-3.0 ml) and drug loading (4-13%). An initial burst of ∼10% followed by a 5-week sustained release phase was obtained. Microparticles with a size <50 μm released in a triphasic manner; an initial burst was followed by a slow release phase and then by a second burst.