Coello A, Meijide F, Núñez E R, Tato J V
Departamento de Química Física, Universidad de Santiago, Lugo, Spain.
J Pharm Sci. 1996 Jan;85(1):9-15. doi: 10.1021/js950326j.
Freezing point depression, delta T/k, and pNa are measured and analyzed for aqueous solutions of trihydroxy (NaTC) and dihydroxy (NaDC and NaTDC) bile salts. The results show the existence of break points in the plot of delta T/k vs molality at 0.018, 0.013, and 0.007 m, respectively, in good agreement with previous published critical micelle concentration values. Above the break point bile salts form aggregates with average aggregation numbers of 2.59 +/- 0.12 (NaTC), 5.82 +/- 0.04 (NaDC), and 5.42 +/- 0.47 (NaTDC). Fractions of bound counterions are also deduced, being close to 0.3 for the three bile salts studied. This indicates that only one counterion is bound for every three monomers in the aggregate. The different structural models published for the bile salt aggregates are discussed.
对三羟基胆汁盐（NaTC）以及二羟基胆汁盐（NaDC和NaTDC）的水溶液进行了冰点降低、ΔT/k和pNa的测量与分析。结果表明，在ΔT/k对质量摩尔浓度的曲线图中，分别在0.018 m、0.013 m和0.007 m处存在断点，这与先前发表的临界胶束浓度值高度吻合。在断点以上，胆汁盐形成聚集体，其平均聚集数分别为2.59±0.12（NaTC）、5.82±0.04（NaDC）和5.42±0.47（NaTDC）。还推导了结合抗衡离子的分数，所研究的三种胆汁盐的该分数接近0.3。这表明在聚集体中每三个单体仅结合一个抗衡离子。讨论了已发表的胆汁盐聚集体的不同结构模型。
