A Temperature Study on Critical Micellization Concentration of the Novel Platelet-Activating Factor Receptor Antagonist E5880 in Water by Electric Conductivity Measurements

Abstract

To clarify the behavior of the novel platelet-activating factor (PAF) receptor antagonist E5880 in aqueous solution, electric conductivity was measured at different temperatures (every 5°C), ranging from 15°C to 50°C. Critical micellization concentration (CMC) of E5880 was dependent on the temperature; at 30°C, the CMC value was smallest (0.143 mM). Below that temperature, the enthalpy for formation of the micelle (Δ H⁰_m) was positive, and the formation of micelles was endothermic; above that temperature, Δ H⁰_m was negative, and the formation of micelles was exothermic.