Dextran Sulfate−Amphiphile Interaction; Effect of Polyelectrolyte Charge Density and Amphiphile Hydrophobicity

Abstract

The interaction between dextran sulfate (DxS), of different charge density, and three cationic amphiphiles varying with respect to hydrophobicity, was investigated by means of equilibrium dialysis and surface tension. The hydrophobicity of the amphiphilies studied increases in the order doxepin-HCl < amitriptyline-HCl < clomipramine-HCl. Dextran sulfate samples with five different charge densities, 0.07, 0.43, 0.7, 1.3, and 1.6 charges per monosachride, were used. The data from both methods clearly indicate that the polyelectrolyte−amphiphile interaction shows a cooperativity that starts at a certain amphiphile concentration and which depends on both the hydrophobicity of the amphiphile and the charge density of the dextran sulfate. A change in the charge density of dextran sulfate and/or amphiphile hydrophobicity affects both the onset of the cooperativity of the interaction and the degree of the cooperativity. The results have also been compared with the data published on related systems.

Structural and thermal study of mesomorphic dodecylammonium carrageenates

“…Self-organization was shown to occur from nano-to macroscopic length scale resulting in formation of various soluble and insoluble surfactant-polymer complexes (PSC) [1][2][3][4][5][6][7][8][9][10]. Substantial efforts have been made to clarify their structures, especially those in the solid state, because PSC represent a new and very interesting class of assembled materials [11].…”

Micropolarity and Microviscosity of Amitriptyline and Dextran Sulfate/Carrageenan‐Amitriptyline Systems: The Nature of Polyelectrolyte–Drug Complexes

“…The general features of the interaction between polyelectrolytes and oppositely charged amphiphilic drug molecules, which have been the subject of a number of studies in our laboratory,3,16–22 can be outlined as follows. The strong association of a polyelectrolyte and oppositely charged amphiphilic drug molecules is essentially due to the electrostatic forces acting between them and the hydrophobic interaction between the apolar moieties of the drug molecules.…”

Amorphous nanodrugs prepared by complexation with polysaccharides: Carrageenan versus dextran sulfate

“…The higher hydrophobicity increased the tendency of the complex to precipitate out of the solution (Persson, Hugerth, Caram-Lelham, & Sundelof, 2000). Moreover, the smaller CIP-CGN nanoplex size could also be attributed to the lower charge density of CGN, where everything else being equal, the lower charge density of CGN resulted in fewer CIP molecules complexed to CGN than to DXT, thus smaller nanoplex was produced from CIP-CGN complexation.…”