Determination of fenticonazole and its impurities by capillary electrophoresis and high performance liquid chromatography

Fenticonazole, a topical antifungal agent containing a stereogenic centre, is used in therapy as a racemic mixture. Five related compounds can be found as impurities in the drug. We propose a HPLC method using as stationary phase a RP-8 column eluted with different gradients of acetonitrile/phosphate buffer (pH 6) for simultaneous determination of the drug and these impurities. We also studied a high performance capillary electrophoresis (HPCE) method for quality control of fenticonazole. The separation of fenticonazole from all its impurities by HPCE was obtained in a relative short capillary (40 cm, effective length 34 cm, 50 mum ID) with a running buffer of 30mM phosphate (pH3) containing 8mM trimethyl-beta -cyclodextrin. Under these experimental conditions very good separation of fenticonazole from each individual impurity is obtained in less than 20 minutes. The choice of cyclodextrin added to the running buffer was dictated by the chiral nature of fenticonazole; trimethyl-beta -cyclodextrin is mainly used as chiral selector. The optimised HPLC and HPCE methods are compared.