Properties of Binary Mixed Micelles of α, ω-Ditetraethylene Glycol Dodecyl Ether and Bile Salts

Abstract

Determination was made of surface tension, polarity of intramicelles, mean aggregation number, hydrodynamic radius and 1H-NMR of binary mixed micelles of bile salts, such as sodium glycochenodeoxycholate (NaGCDC) and sodium glycoursodeoxycholate (NaGUDC) and nonionic surfactants, such as α, ω-ditetraethylene glycol dodecyl ether (C122E4) and octaethylene glycol mono-n-decyl ether (C10E8) for the following four systems; (1) NaGCDC-C122E4 system, (2) NaGCDC-C10E8 system, (3) NaGUDC-C122E4 system and (4) NaGUDC-C10E8 system.Micellar composition for each system was noted to change from nonion-rich to bile salt-rich with mole fraction of a bile salt and the microenvironment of intramicelles for C10E8 systems became more hydrophobic compared to C122E4 systems. Mean aggregation number of mixed micelles for C10E8 systems abruptly decreased with increase in mole fraction of bile salts in the range of the low mole fraction, while for C122E4 systems, was essentially constant. From the results of 1H-NMR, NaGUDC molecular orientation in mixed micelles differed from that of a NaGCDC molecule. Schematic models of the mixed micelles were established based on the present results.