Thermodynamic And Spectroscopic Features Of The Behaviour Of Amphotericin B In Aquoes Medium
ROMANINI, DIANA; AVALLE, GABRIELA; NERLI, BIBIANA; PICÓ, GUILLERMO
Lugar: Shannon; Año: 1999 vol. 77 p. 69 - 69
Abstract The interaction between amphotericin B molecules in aqueous medium solution was studied using absorption andcircular dichroism approaches. The results showed that at concentrations below 1 mM of amphotericin B, an equilibrium between the monomer and aggregate occured with a constant of approximately 0.6=106 My1. The aggregate formation constant was dependent on the experimental conditions of the medium: its value increased atacidic pH values, while alkaline medium induced the equilibrium displacement to the monomer formation. Eitherneutral salts or chaotropic agents such as urea prevented the formation of the aggregate. The presence of netelectrical charge on the amine and carboxyl groups plays a role in the thermodynamic stability of the aggregate. Ahydrophobic effect was also found between the monomer form and the water molecules of neighbours. In theaggregate formation water molecules were released contributing to an increase in the entropic change. Q 1999 Elsevier Science B.V. All rights reserved.