Department of Chemistry, North Eastern Hill University, NEHU Campus, Shillong 793 022, India.
J Colloid Interface Sci. 2011 May 15;357(2):434-9. doi: 10.1016/j.jcis.2011.02.020. Epub 2011 Feb 15.
The salicylate ion increases the rate of bile flow (choleretic effect) and bile salts are known to affect the colonic absorption of oxalate. Owing to this physiological relevance of salicylate and oxalate ions, critical micelle concentration (cmc) values of sodium deoxycholate (NaDC) were determined in aqueous sodium oxalate, sodium salicylate, and sodium chloride solutions by using surface tension, fluorescence, and EMF methods. The results indicate, besides a counterion effect, the influence of coanions on the cmc. In the range from 25 to 40 °C, cmc increases almost linearly with temperature. In the temperature range from 30 to 40 °C, the counterion binding constant β of NaDC micelles has the same value (0.17±0.01) in the presence of sodium chloride and sodium salicylate. On the other hand, in sodium oxalate solution β=0.05±0.02 when oxalate concentration is less than or equal to c* and β=0.48±0.04 above c*, where c*≈0.038 mol kg(-1). EMF measurements also supported this type of counterion binding to NaDC micelles in sodium oxalate solutions. In sodium oxalate solution, at c* a change in the shape of deoxycholate micelles is expected to take place. Salicylate, oxalate, and chloride coanions have a similar effect on the adsorption of NaDC. This study reveals that the choleretic effect of salicylate is not due to the influence of salicylate ions on the micellization of NaDC.
水杨酸根离子增加胆汁流量（利胆作用），并且胆汁盐已知会影响草酸在结肠中的吸收。由于水杨酸根离子和草酸盐离子具有这种生理相关性，因此通过表面张力、荧光和 EMF 方法在含有草酸钠、水杨酸钠和氯化钠的水溶液中测定了脱氧胆酸钠（NaDC）的临界胶束浓度（cmc）值。结果表明，除了抗衡离子效应外，共离子对 cmc 也有影响。在 25 至 40°C 的范围内，cmc 随温度几乎呈线性增加。在 30 至 40°C 的温度范围内，在存在氯化钠和水杨酸钠的情况下，NaDC 胶束的抗衡离子结合常数β具有相同的值（0.17±0.01）。另一方面，在草酸钠溶液中，当草酸盐浓度小于或等于 c时β=0.05±0.02，当草酸盐浓度大于 c时β=0.48±0.04，其中 c*≈0.038 mol kg(-1)。EMF 测量也支持了这种类型的抗衡离子与 NaDC 胶束在草酸钠溶液中的结合。在草酸钠溶液中，预计在 c*时脱氧胆酸盐胶束的形状会发生变化。水杨酸盐、草酸盐和氯离子共离子对 NaDC 的吸附具有相似的影响。本研究表明，水杨酸的利胆作用不是由于水杨酸离子对 NaDC 胶束化的影响所致。
