Bile acid salts are amphiphiles that have planar polarity: the convex surface (the β side) of their steroid skeleton is hydrophobic, whereas the concave surface (the α side) is hydrophilic. Lactone and lactam derivatives of bile acid salts have reduced hydrophobicity on the convex surface (β side) of the steroid skeleton, but they are still able to build micelles. In the vicinity of their critical micellar concentration (CMC), they probably form Small's primary micelles. In this work, it is shown that retention capacities (reverse‐phase high‐performance liquid chromatography) are linearly dependent on temperature, for each tested bile acid. The parameters of this linear dependence (intercept and slope) can be used to describe the hydrophobicity of the analyzed bile acid salts. The first and the second principal components, derived from the covariance matrix of temperature dependence of retention capacity, can also be used as hydrophobicity parameters of the analyzed bile acid salts. There is a strong correlation between the CMC values and the values of the hydrophobicity parameters of the convex surface (the β side) of the steroid skeleton: the CMC values decrease as the hydrophobicity of the β side of the steroid skeleton decreases.

中文翻译：

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胆甾类骨架中胆盐与内酯或内酰胺基团的疏水性和自缔合（胶束化）

胆汁酸盐是具有平面极性的两亲物：其类固醇骨架的凸表面（β侧）是疏水的，而凹表面（α侧）是亲水的。胆汁酸盐的内酯和内酰胺衍生物在类固醇骨架的凸面（β侧）具有降低的疏水性，但它们仍然能够形成胶束。在其临界胶束浓度（CMC），它们可能形成了Small的主要胶束。在这项工作中，证明了每种测试的胆汁酸的保留能力（反相高效液相色谱法）与温度呈线性关系。该线性依赖性的参数（截距和斜率）可用于描述所分析的胆汁酸盐的疏水性。从保留能力的温度依赖性的协方差矩阵得出的第一和第二主成分也可以用作分析胆汁酸盐的疏水性参数。CMC值与类固醇骨架凸面（β侧）的疏水性参数值之间存在很强的相关性：CMC 甾族化合物骨架的β侧的疏水性降低时，其值降低。