Characterization of partitioning behavior of cephalosporins using microemulsion and micellar electrokinetic chromatography

Electrokinetic chromatography (EKC) was introduced to determine the partiti oning behavior of various cephalosporins (cefpim, cefpirom, cefaloridin, ce faclor, cephalexin, cefuroxim, cefotaxim) in microemulsions (ME) and micell ar (MC) systems. The partitioning behavior of cephalosporins in microemulsi ons was characterized calculating the capacity factor. The required paramet ers for the determination of the capacity factor (mu(aq) and mu(me) are the electrophoretic mobilities of the solutes in the aqueous phase and the mic roemulsion phase, mu(eff) is the effective mobility in the microemulsion so lution) were measured by EKC using cationic surd anionic microemulsion syst ems consisting of the surfactants/n-heptane/1-butanol/10 mM phosphate buffe r solution, pH 7.0. Electrokinetic chromatography was shown to be a useful method to quantify the partitioning behavior of drugs in oil/water microemu lsion. The logarithm of the capacity factor was correlated with the logarit hm of the 1-octanol/water partitioning coefficients.