Analysis of active ingredients and preservatives in creams by capillary electrochromatography (CEC)

Capillary electrochromatography (CEC) is an analytical method of growing in terest to the pharmaceutical industry. Because CEC is a combination of high -performance liquid chromatography (HPLC) and capillary electrophoresis (CE ) it has the advantages of the high selectivity of HPLC and the high effici ency of CE. The capillaries can be packed with different packing materials. The mixed-mode phase consisting of a strong cation exchanger and alkyl cha ins on the silica surface has some advantages over conventional reversed-ph ase (RP) packing materials. In this article the authors describe the use of CEC to separate the active ingredients and preservatives in creams from di fferent manufacturers. On the basis of the high efficiency of CEC it was po ssible to develop one isocratic method for all the compounds in the differe nt samples. The method was validated with regard to identification, reprodu cibility, linearity, limit of detection, and quantitation.