Effect of electrolytes on the mechanism of clouding process and physico-chemical quantities of non-ionic surfactant and ciprofloxacin hydrochloride mixture

Abstract

An investigation of the clouding behaviour of the aqueous solution of ciprofloxacin hydrochloride (CIPH) + Triton X-100 (TX-100) under different electrolytes media was performed by the phase-changing measurement method. The CP of the resultant mixture has been studied in aqueous solutions of some organic and inorganic salts (sodium carbonate (Na2CO3), sodium oxalate (NaOxa), sodium acetate (NaOAc) and magnesium sulphate (MgSO4)). The CP values of TX-100 (50 mmol kg−1) + CIPH (1 mmol kg−1) solution decreases in the presence of all electrolytes while the CP values satisfy the sequence: CP (aq. NaOAc) > CP (aq. MgSO4) > CP (aq. Na2CO3) > CP (aq. NaOxa). The decrease in the solubility of employed solution in the aq. electrolytes media was observed and obtained maximum solubility in aqueous NaOAc and minimum solubility in the aqueous NaOXa medium. The obtained positive Gibbs-free energy ( Δ G c 0 ) demonstrates the nonspontaneous nature of phase separation while the extent of nonspontaneity exhibits the reduction with enhancing electrolyte concentrations. The Δ H c 0 and Δ S c 0 values depict the existences of electrostatic and hydrophobic interactions between TX-100 and CIPH in aq. electrolytes solutions and the clouding process is enthalpy controlled. Entropy-enthalpy compensation variables were computed.