Purity assessment of crystalline zearalenone.

Commercially available solid zearalenone (ZON) to be used as a certified liquid calibrant (BCR-699) in a project funded by the European Commission within the Standard Measurement and Testing program was characterized and its purity determined. The degree of purity of the ZON was examined by UV spectrophotometer, liquid chromatography (LC) with diode array and fluorescence detection, 1H and 13C-NMR spectrometry, LC-mass spectrometry (LC/MS/MS), ion chromatography (IC), and differential scanning calorimetry (DSC). The diagrams obtained from DSC analysis and the UV spectrum showed no detectable impurities. Likewise, no impurities were observed by LC analysis with both diode array and fluorescence detection. IC determination revealed negligible contamination of ZON with chloride of 0.020 +/- 0.005% and nitrate of 0.016 +/- 0.006%. Zearalanone (ZAN) was identified as one of 2 minor (0.2%) impurities by LC/MS/MS. The 1H-NMR measurements revealed an additional peak, which has not been previously reported in the literature. It could be identified as part of the ZON spectrum as the signal arising from the phenolic proton attached to C4'. The manufacturer states an additional contamination with 0.2% methylene chloride, which could be confirmed to an extent of 0.1% by 1H-NMR. Minor impurities, whose structures remain unknown, were discovered at 3.5 and < 1 ppm. Total percentage of impurities based on NMR measurement was estimated not to exceed 1%. A purity of 99.5% with a tolerance of +/- 0.5% was finally attributed to the ZON studied in this project.

[An unusual case of pyoderma gangrenosum with necrotizing granulomatous dermatitis]. / Ein ungewöhnlicher Fall eines Pyoderma gangraenosum mit nekrotisierender granulomatöser Dermatitis.

Four distinctive clinical and histological variants of pyoderma gangrenosum have been proposed: (1) ulcerative, (2) pustular, (3) bullous, and (4) vegetative. The rate of progression and associated systemic diseases, as well as the histopathologic changes, can vary considerably between these clinical variants. A 64-year-old man presented with ulcerative pyoderma gangrenosum associated with renal cell carcinoma and IgA paraproteinemia; he responded to oral thalidomide. Histopathology revealed unusual findings with signs of leukocytoclastic vasculitis, basophilic degeneration of collagen and zones of suppuration with a palisaded histiocytic and epithelioid granulomatous infiltration throughout the dermis.