Determination of homotaurine as impurity in calcium acamprosate by capillary zone electrophoresis

A method is reported which allows the quantification of homotaurine as an i mpurity in the drug. After addition of taurine as an internal standard, the sample is derivatised with fluorescamine at ambient temperature in 10 mM b erate buffer, pH 9.2. The analytes are separated by capillary zone electrop horesis in a 31.2 cm (21 cm to the detector)x100 mu m I.D. fused-silica cap illary at a potential of +7 kV and 25 degrees C. A 40 mM berate buffer, pH 9.2, is used as the electrolyte and detection is carried out at 205 nm. The validation tests showed that the method is reliable between 0.01% and 0.15 % (m/m) of homotaurine with respect to the active drug. The limits of quant itation (0.01%, m/m) and detection (0.004%, m/m) allows to control the homo taurine content of the drug substance for which the maximum tolerated level is 0.05% (m/m). The proposed procedure (derivatisation and separation) dev eloped in CE is rapid (20-25 min) by comparison to that currently used in H PLC (75 min). Satisfactory agreement was found between several batches of a camprosate analysed by CE and HPLC. (C) 1999 Elsevier Science B.V. All righ ts reserved.