| Summary: | 碩士 === 國立成功大學 === 化學工程學系碩博士班 === 90 === This study investigated the equilibrium and dynamic surface tension behavior of medicinal Pulmicort® nebulising suspensions (budesonide suspensions), budesonide suspensions, and polysorbate 80 solutions. The equilibrium and dynamic surface tensions were measured by the Wilhelmy plate and drop volume methods, respectively, and mathematical models were then developed to describe the dynamic adsorption behavior of dispersion systems. The results indicated that the equilibrium surface tension behavior of the medicinal budesonide suspension was not effected by the presence of budesonide, but the dispersant polysorbate 80 in the formulation played an important role. Based on the theoretical analysis of the equilibrium surface tensions, it was found that the maximum surface concentration of budesonide was larger than that of polysorbate 80, but the surface activity of polysorbate 80 was much higher than that of budesonide. As a result, the equilibrium surface tension behavior of the Pulmicort® nebulising suspension was dominated by polysorbate 80.
The dynamic surface tensions of the Pulmicort® nebulising suspension were found higher than those of budesonide or polysorbate 80 at a certain period of adsorption time. This result suggests that the dynamic adsorption behavior of the Pulmicort® nebulising suspension was not totally controlled by the higher surface active component, polysorbate 80. When the equilibrium adsorption was approached, the dynamic surface tension behavior of the Pulmicort® nebulising suspension was then dominated by polysorbate 80. From the equilibrium and dynamic surface tension behavior, one can conclude that the influence of the dispersant polysorbate 80 must be considered in evaluating the adsorption behavior of the medicinal budesonide suspension. When a Pulmicort® nebulising suspension is applied in the lung, polysorbate 80 with high surface activity may inhibit the surface tension lowering ability of lung surfactants.
Mathematical models were applied to analyze the dynamic adsorption behavior of budesonide and polysorbate 80, and it appears that their dynamic adsorption processes were mixed-kinetic controlled. Moreover, a dynamic adsorption mathematical model with the consideration of dissolution effect was developed and was successfully applied to the dispersion systems of catanionic surfactants CP·DS and DTMA·DS.
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