SOLUBILIZATION AND PRECIPITATION OF CHOLESTEROL IN AQUEOUS-SOLUTION OF BILE-SALTS AND THEIR MIXTURES

Solubilization of cholesterol by mixed micelles of sodium chenodeoxych olate with sodium ursodeoxycholate was investigated in carbonate-tetra borate buffer (Kolthoff) solution at pH 10 and 37 degrees C. It was fo und that the mixing of the two bile salts gives a negatively synergeti c effect on solubilization of cholesterol. The solubilizing power of b ile salts for cholesterol was remarkably influenced with the change in mole fraction of sodium ursodeoxycholate (X(UDC)). The behavior of bi le salt solutions saturated with cholesterol was examined by measuring the surface tension. Two break points were observed in the curves of surface tension vs. concentration. The break points seem to correspond to a CMC in the absence of solubilized cholesterol and another CMC in the presence of solubilized cholesterol inside bile salt micelle.