title: GLC and NMR analysis of isomeric impurities in the new anti-inflammatory agent benoxaprofen.
abstract: GLC and NMR methods are described for the determination of four possible isomeric impurities in the novel anti-inflammatory agent benoxaprofen. The 2- and 3-chlorophenyl isomers were determined by GLC after alkaline hydrolysis and subsequent methylation. A rapid NMR procedure, using the lanthanide shift reagent tris- (1, 1, 1, 2, 2, 3, 3-heptafluoro- 7, 7-dimethyl- 4, 6-octanedionato)-europium, was developed for the 6- and 7- (alpha-methylacetic acid) isomers. Similar methodolology, with tris-(3-heptafluorobutyryl-d-camphorato)europium, enabled the determination of the enantiomer ratio for benoxaprofen. For the positional isomers, the limits of detection were 0.05% by GLC and 0.2% by NMR.
mesh_terms: D000893:Anti-Inflammatory Agents / Q000032:analysis*; D001583:Benzoxazoles / Q000032:analysis*; D002849:Chromatography, Gas; D007536:Isomerism; D009682:Magnetic Resonance Spectroscopy; D011422:Propionates; D013237:Stereoisomerism
chemical_list: D000893:Anti-Inflammatory Agents; D001583:Benzoxazoles; D011422:Propionates; C011677:benoxaprofen