Determination of ibuprofen and flurbiprofen in pharmaceuticals by capillary zone electrophoresis

Capillary zone electrophoresis with spectrophotometric detection was used for the determination of ibuprofen (IB) and flurbiprofen (FL) in pharmaceuticals. The separation was carried out in a fused silica capillary (60 cm × 100 μm i.d. effective length 45 cm) at 30 kV with UV detection at 232 nm. The optimized background electrolyte was 20 mM N-(2-acetamido)-2-aminoethanesulfonic acid (ACES) with 20 mM imidazole and 10 mM α-cyclodextrin of pH 7.3. 2-Naphthoxyacetic acid was used as internal standard. A single analysis took less than 5 min. Rectilinear calibration ranges were 2–500 mg l−1 for IB and 1–60 mg l−1 for FL. The relative standard deviations (R.S.D.) values (n = 6) were 1.53% for IB and 1.29% for FL (for 200 mg l−1 IB and 10 mg l−1 FL). This validated method has been successfully applied for the routine analysis of 10 commercially available pharmaceutical preparations (syrup, tablets, cream and gel).