DETERMINATION OF FLUFENAMIC, MECLOFENAMIC AND MEFENAMIC ACIDS BY CAPILLARY ELECTROPHORESIS USING BETA-CYCLODEXTRIN

The possibility of separating flufenamic, meclofenamic and mefenamic a cids by capillary electrophoresis was studied. The best approach invol ved combining a suitable pH of the carrier electrolyte (pH 12.0) with the host-guest complexation effects of beta-cyclodextrin. A running bu ffer consisting of 30 mM phosphate buffer (pH 12.0), 2 mM P-CD and 10% (v/v) acetonitrile was found to provide a very efficient and stable e lectrophoresis system for the analysis of fenamic acids by capillary z one electrophoresis. Responses were linear from 0.4 to 40 mu g/ml for the three drugs with detection limits of about 0.3 ng/ml. Intra- and i nter-day precision values of about 1-2% R.S.D. (n = 11) and 3-4% R.S.D . (n = 30), respectively, were obtained. The method is highly robust a nd no breakdowns of the current or capillary blockings were observed f or several weeks. The general applicability of this rapid CZE procedur e (migration times less than 12 min) is demonstrated for several pract ical samples, including serum, urine and pharmaceuticals. (C) 1998 Els evier Science B.V.