| 研究実績の概要 |
I have successfully investigated the effects of surfactants on the entrapment yield of the hydrophilic molecule - calcein, in lipid vesicles prepared by multiple emulsion method. The experiments were conducted using three different surfactants, Tween 80, Pluronic F68, and BSA, in the W2 phase of W1/O/W2 multiple emulsion prepared using microchannel emulsification technique. Three mechanisms were proposed to explain the stabilization effects of the surfactants with respect to the entrapment yields of the hydrophilic fluorescent marker, calcein. At high concentrations (ca. 3.0 wt%), reversed-micellar transport of calcein from the internal to the external water phase is predominant in Pluronic F68 stabilized lipid vesicles; whereas, for Tween 80 stabilized vesicle suspensions at such high concentration, both destabilization/solubilization effects and reversed-micellar transport of calcein are at play. With decreasing concentrations of the Tween 80, the entrapment yield improves up to certain threshold concentration, below which poor entrapment ensues due to insufficient amount of the surfactant. Hence, calcein - a model of hydrophilic drug - can be efficiently entrapped (ca. 80%) in lipid vesicles at lower concentrations of the food grade surfactant, Tween 80 (ca. 0.1 and 0.05 wt%). The results of this study, therefore, could provide clues on the design of experimental conditions for improved entrapment yields of hydrophilic physiologically active substances.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
The progress of my research is at the expected rate. Though there were little challenges I encountered, just like most researchers, I was able to overcome them in due time. I have successfully determined the best surfactants' indices (type and concentration) needed for optimum entrapment yield of a model hydrophilic drug, calcein, in lipid vesicles. Based on the results so far, I have prepared two manuscripts for publication.
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| 今後の研究の推進方策 |
At present, I have started the encapsulation of bioactive materials based on the current research achievement. I will be working with both hydrophilic an hydrophobic functional materials, namely, 5-fluorouracil (hydrophilic anticancer agent), metformin (hydrophilic oral anti diabetic agent), and glibenclamide (hydrophobic oral anti diabetic agent). Principally, Tween 80 (0.1, 0.05, and 3.0 wt%) would be used as emulsifier in the continuous phase for the encapsulation of the various drugs in lipid vesicles using multiple emulsion method. Similarly, 3.0 wt% each of Plutonic F68 and Casein Na (in place of BSA; both found to have similar yield of entrapment) would also be used.
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