Characterization of micellar solubilization of antibiotics using micellar electrokinetic chromatography

Micellar electrokinetic chromatography (nMEKC) method was applied to the determination of the partition behaviour between water and micelle for a group of antibiotics using sodium dodecyl sulphate (SDS) as an anionic model surfactant. In the method, the running buffer contains both the micelles and the drug, and the injected solution contains the same concentration of the micelles as the running buffer but no drug. The mobility of the drug can be measured from a negative peak recorded in the chromatogram. The required parameters for the determination of the capacity factor were measured by the MEKC technique. Thermodynamic properties such as enthalpy and entropy changes of micellar solubilization were calculated from the temperature dependence of the partition coefficients. The critical micellar concentrations (CMC) of the SDS salt were determined in phosphate solutions at pH 7 at different temperatures using the MEKC. The method described in this article based on MEKC is efficient and very fast in order to determine parameters for characterizing micellar solubilization of drugs.