Control of drug loading efficiency and drug release behavior in preparation of hydrophilic-drug-containing monodisperse PLGA microspheres
We prepared monodisperse poly(lactide-co-glycolide) (PLGA) microspheres containing blue dextran (BLD)—a hydrophilic drug—by membrane emulsification technique. The effects of electrolyte addition to the w2 phase and significance of the droplet size ratio between primary (w1/o) and secondary (w1/o/w2) emulsions during the preparation of these microspheres was examined. The droplet size ratio was evaluated from the effect of stirring rate of the homogenizer when preparing the primary emulsion. The drug loading efficiency of BLD in these microspheres increased with stirring rate. It increased to approximately 90% when 2.0% NaCl was added to the w2 phase. Drug release from these microspheres was slower than that when they were prepared without electrolyte addition. Despite the very high efficiency drug release was gradual because BLD was distributed at the microspheres core. Relatively monodisperse hydrophilic-drug-containing PLGA microspheres with controlled drug loading efficiency and drug release behavior were prepared.
KeywordsDrug Release Droplet Size Emulsion Droplet PLGA Microsphere Drug Release Behavior
This study was supported by the “High-Tech Research Center” Project for Private Universities with a matching fund subsidy from the Ministry of Education, Culture, Sports, Science and Technology (MEXT), 2004–2008. This study was mainly conducted at the Kimiko Makino Laboratory and at the Center for Drug Delivery Research at the Tokyo University of Science.
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