中性芳香族溶质在脂质体电动色谱中的热力学分配行为

脂质体电动色谱是一种理想的评价药物与生物膜相互作用的模型. 在288～323 K范围内测定了中性芳香族溶质在脂质体电动色谱中的分配系数, 通过三项式拟合Van't Hoff图获得了一系列的热力学参数, 研究了溶质在脂质体电动色谱中的热力学分配行为. 结果表明, 分配系数随体系温度的升高和苯环所带亚甲基数目的增加而增大. 从288到323 K, ΔH＞0, －TΔS＜0, ΔG＜0, 溶质在脂质体电动色谱中的分配过程为熵驱动过程. 从288到298 K, 脂质体电动色谱分配系统的ΔC_p为负值, 其表现行为与经典疏水作用一致. 从303到323 K, 脂质体电动色谱分配系统的ΔC_p为正值, 其表现行为与经典疏水作用不完全吻合. ΔH和ΔS呈线性关系, 该分配系统存在焓熵补偿.

Thermodynamic Partitioning Behavior of Neutral Aromatic Solutes in Liposome Electrokinetic Chromatography

Liposome electrokinetic chromatography (LEKC) is a good model evaluating the interaction of a drug with a biomembrane. Partition coefficients of neutral aromatic solutes in LEKC between 288～323 K were measured. A series of thermodynamic parameters were obtained by third-order polynomial fitting Van't Hoff plots. The thermodynamic partitioning behavior of those solutes was investigated. The results showed that the partition coefficient became greater with the increment of temperature and the number of CH₂ functional groups on benzenering. During the whole experiment temperature range (288～323 K), ΔH and TΔS were positive while ΔG was negative, which indicated that the partitioning process of solutes in LEKC system was entropy-driven. From 288 to 298 K, ΔC_p was negative and the LEKC partitioning system exhibited typical hydrophobic effect. From 303 to 323 K, ΔC_p was positive and the LEKC partitioning system betrayed a typical hydrophobic effect. A linear relationship between ΔH and ΔS indicated the occurrence of enthalpy-entropy compensation in the LEKC system.