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A simple, fast capillary electrophoresis method for determining the total ketoprofen content in an oral pharmaceutical formulation is proposed. The addition of 75 mM of heptakis(tri- O-methyl)-beta-cyclodextrin to the background electrolyte allows the quantitation of the enantiomeric impurity of ( R)-(-)-ketoprofen contained in the formulation. A relative limit of detection is proposed as a measure of the lowest detectable enantiomeric impurity and the results show that the method can detect the minor enantiomer at levels as low as 0.04% in ( S)-(+)-ketoprofen. The chiral method was validated following ICH recommendations and the quality parameters obtained show the suitability of the proposed method. The analysis of samples examined during the course of a stability study under chiral and achiral conditions revealed that the total ketoprofen content did not change significantly with time and the enantiomeric impurity range was 0.1-0.4%.

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E,E[4,4'- bis(2-sulfostyryl)biphenyl] (DSBP) is a stilbene-type fluorescent whitening agent (FWA) widely used by the textile and detergent industries. UV and fluorescence spectrophotometry are used to examine its stability against hypochlorite, which may restrict its use and may have an adverse environmental impact because a considerable fraction of the FWA used during the washing process remains in the washing liquor and is discharged into sewers. The degradation of this whitening agent is catalyzed by several transition metal ions usually present in tap water. The catalytic effect decreases in the following sequence for the metal ions tested: Fe2+ > Mn2+ > Cu2+ = Fe3+. The addition of an appropriate chelating agent such as Dequest® 2006 [diethyleneaminepenta(methylenephosphonic) acid] in a 20:1 mole ratio completely inhibits the process; by contrast, other complex-forming agents such as EDTA accelerate it.