Effect of Various Electrolytes on the Phase Separation and Thermodynamic Properties of p‐Tert‐Alkylphenoxy Poly (Oxyethylene) Ether in the Absence/Presence of Drugs

Cloud point (CP) measurements of 4‐(1,1,3,3‐tetramethylbutyl) phenyl‐polyethyleneglycol (Triton X‐100 (TX‐100)) were performed in aqueous solution in the presence of drug Amikacin sulfate (AS)/Neomycin sulfate (NS)/(AS/NS+ different inorganic salts). In aqueous solution, the CP values of TX‐100 first decrease with increasing concentration and then increase with increasing surfactant concentration. The CP values of TX‐100 solutions were found to increase with the increasing concentration of the AS/NS drug. The CP values of TX‐100‐AS/NS mixtures were also observed to decrease with the increase of the concentration of salt. Different thermodynamic parameters such as standard free energy (ΔGc0), standard enthalpy (ΔHc0) as well as the standard entropy (ΔSc0) change of phase separation were calculated and discussed in relation to molecular interactions.