Binding of Bile Salts to an Amphiphilic Polysulfonate Modified with Cholesterol Moieties

Abstract

ABSTRACT:A hydrophobically modified polysulfonate bearing a small mole percent (5 mol %) of cholesteryl moieties forms an intermolecularly bridged flower micelle in water, arising from intermolecular associations of the polymer-bound cholesteryl groups. Binding of sodium cholate (SC) to this polymer micelle in water was investigated using 1 H NMR spin-spin relaxation time, static light scattering, quasi-elastic light scattering, and fluorescence techniques. The intermolecular association of the polymer-bound cholesteryl groups was disrupted, to some extent, by the addition of SC, resulting in the formation of complexes of the polymer-bound cholesteryl groups and SC. To investigate interactions between the polymer-bound cholesteryl groups and SC, the cholesteryl groups were labeled with a naphthalene moiety. Fluorescence spectra of the naphthalene labels and NMR spin-spin relaxation time data suggested that interactions between the aggregates of the polymer-bound cholesteryl groups and SC occurred below a critical micelle concentration of SC in water.

Synthesis and characterization of polycholesteryl methacrylate–polyhydroxyethyl methyacrylate block copolymers

“…49 Other applications of copolymers bearing cholesterol side-chains include optical data recording and storage 15,18,[50][51][52] and solution self-assembled fluorescent probes. [53][54][55][56][57][58] Many of the examples noted earlier comprise random copolymers with main and side-chain cholesterol units. However, we are interested in synthesizing well-defined block copolymers comprising side-chain cholesterol units in one block and moieties capable of hydrogen bonding in the second block.…”

Self-Aggregation Phenomenon of Promazine Hydrochloride Under the Influence of Sodium Cholate/Sodium Deoxycholate in Aqueous Medium

“…mc X mc f [13] As said by the pseudo phase separation model, [42] the standard Gibbs energy of micellization ( 0 m ΔG ), for PMZ and bile salts as well as their mixtures can be evaluated by taking into consideration the degree of dissociation (g) of the counter ion to the micelle 0 m ΔG = (2 g) RT lnX cmc [14] where X cmc , g, R and T are the cmc expressed in mole fraction units, degree of dissociation, gas constant and temperature, respectively. The non-ideality in the mixed micelle due to interaction can be assessed by evaluating molar excess standard free energy of micellization ( ex G ).…”

“…)-(13). Activity coefficients evaluated by various recommended models, are less than unity at all 1 and temperatures which point out attractive nonideal behavior of the mixed systems; however, differences between the activity coefficient suggest significant role of entropy in mixing of amphiphiles(Tables 1-2).…”

“…[6][7][8][9] The bile salts are eliminated from the blood by the liver and buried into the bile and their physiological concentrations are of concern with respect to the interaction of these detergents with plasma membranes. [10,11] In addition, they are also extensively used in many application fields, together with cosmetics, food production, molecular recognition, [12] new drug development [13] and adjusting supramolecular self-assembly structures. [14] From fundamental as well as applied science perspective, it is important to understand the physicochemical behavior of bile salt-polymer [15] or bile salt-surfactant [16] aggregates (bile salt-drug aggregate being a special case) as it draws correlation with gall stone dissolution, food metabolism, lipid digestion and so on.…”

Controlled radical polymerization of styrene initiated by diethyldithiocarbamate‐mediated iniferters

“…However, this method is not useful for the polymerization of methacrylic acid or acrylic acid monomers, because such systems need basic ligands such as bipyridyl compounds. The RAFT process is also a convenient method for the architecture of hydrophilic polymers using water‐soluble chain transfer reagents such as 4‐cyanopentanoic acid dithiobenzoate 14–16. More recently, we demonstrated that density functional theory calculations provide a reliable and quantitative prediction of the trends in C‐S bond dissociation energies for several model compounds as photoinitiator.…”