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Journal ArticleDOI

Concentration limits in association colloid solutions

01 Jan 1954-Journal of Colloid Science (Academic Press)-Vol. 9, pp 66-80
About: This article is published in Journal of Colloid Science.The article was published on 1954-01-01. It has received 37 citations till now. The article focuses on the topics: Colloid.
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Journal ArticleDOI
TL;DR: While bile salts increase slightly the solubility of relatively nonpolar molecules (such as cholesterol or fatty acids), they have a striking capacity to render soluble certain important insoluble molecules of biological importance such as phospholipids and monoglycerides.
Abstract: Bile salts, which are soluble amphiphiles, possess a unique molecular structure when compared with typical detergent molecules. In water, bile salts form small aggregates called micelles. The behavior of bile salt micelles is quite different from micelles formed by detergents. Bile salt micelles are smaller, more highly charged and of different structure than detergent micelles. Bile salts form mixed micelles with a variety of other soluble and insoluble lipidic substances. While bile salts increase slightly the solubility of relatively nonpolar molecules (such as cholesterol or fatty acids), they have a striking capacity to render soluble certain important insoluble molecules of biological importance such as phospholipids and monoglycerides. In fact as little as 1 mole of bile salt can solubilize 2 moles of lecithin. Solubilization takes place in mixed bile salt micelles of unique structure and properties. These mixed micelles incorporate very appreciable amounts of insoluble molecules, such as fat-soluble vitamins

445 citations

Journal ArticleDOI
TL;DR: The relationship between various kinds of solubilization and the formation of mesophases is elucidated in this paper, where three processes by which mesomorphous phases form are discussed.
Abstract: The relationship between various kinds of solubilization and the formation of mesophases is elucidated. In aqueous solutions of association colloids there are three processes by which mesomorphous phases form: (i) the separation of the micellar substance in mesomorphous form on reduction of the water content, (ii) the separation of the micellar substance at lower concentrations, from the c.m.c. upwards, as a result of the changes that the micelles undergo on solubilization of foreign amphiphilic and lipophilic substances, and (iii) below the c.m.c. through the formation of aggregates between the solubilizate and the molecules or ions of the association colloids. The last of these processes is typical of the solubilization of fatty acids and liquid monohydric alcohols. In systems of sparingly soluble amphiphilea that do not give micellar aqueous solutions but take up water with swelling, mesophases often form through this “solubilization” of water, a process that is often promoted by the presence ...

186 citations

Journal ArticleDOI
TL;DR: The role of bile salts as biological surfactants and their participation in the dissolution of cholesterol gallstones, lipid solubilizatlon and absorption, and their ability to cause lysis of membrane surfaces has been discussed.

129 citations

Book ChapterDOI
TL;DR: This chapter discusses the physical–chemical properties of bile acids and their salts and describes how the anions are held together mainly by ion–ion and ion–dipole interactions and the crystal packing patterns are remarkably similar.
Abstract: Publisher Summary This chapter discusses the physical–chemical properties of bile acids and their salts. It covers only those aspects of the physical chemistry of bile acids and their salts that have progressed substantially during the intervening years. The common bile acids and salts possess a characteristic molecular structure shown schematically in the chapter. A compilation of critical physical constants for the common bile acids and their salts is given in the chapter. Crystal and molecular structures of three bile salt hydrates have been solved. The crystallographic data show that all are monoclinic with two molecules in each unit cell. Whereas the anions are held together mainly by ion–ion and ion–dipole interactions between the counterions and the carboxylate and hydroxyl groups to which water molecules contribute, the crystal packing patterns are remarkably similar. On the basis of surface and bulk interaction with water, bile acids are classified as insoluble amphiphiles and bile salts as soluble amphiphiles.

77 citations

Journal ArticleDOI
01 Mar 1971
TL;DR: In this paper, the vapour-pressure values for aqueous solutions of sodium cholate, desoxycholate and dehydrocholate measured by a thermistor method were calculated.
Abstract: From the vapour-pressure values for aqueous solutions of sodium cholate, desoxycholate and dehydrocholate measured by a thermistor method the osmotic coefficients, the activity of water and the mean activity of the bile salts have been calculated. In the case of sodium cholate and desoxycholate these quantities were found to vary with concentration in a manner characteristic of association colloid solutions and pointing to an association process in the concentration range 0.013–0.11 and 0.004–0.05 molal, respectively. For the dehydrocholate the evidence of an association is less conclusive.

69 citations