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Ping Wang 《Pesticide biochemistry and physiology》2005,82(3):197-204
The stereoselective degradation of ethofumesate in turfgrasses and several agricultural soils was investigated to provide details of the fate of this chiral herbicide. Racemic ethofumesate was either foliar applied to two species of turfgrass or fortified into four types of agricultural soils. (+)- and (−)-Enantiomers were extracted and analyzed by a validated chiral HPLC method which involved extraction of samples with organic solvent followed by separation on cellulose-Tris-(3,5-dimethylphenylcarbamate)-based chiral column and quantification by UV absorbance at 230 nm. Mean recoveries of each enantiomer fortified at 0.5, 5, and 10 μg g−1 ranged from 82.3 ± 5.84 to 92.5 ± 2.87% in turfgrasses and from 86.0 ± 5.09 to 98.1 ± 2.51% in soil. As a measure of this composition, the enantiomeric ratio (ER) was used, defined as the concentration ratio of (+)/(−)-enantiomer. Similarly, preferential degradation of the (−)-enantiomer was observed in both grass species with the largest ER of about 3 and in one of the test soil with ER = 1.65, resulting in residues enriched with (+)-enantiomer. This stereoselective degradation in this soil led to significant difference on half-lives between the two enantiomers. No stereoselective degradation was observed in other soils. 相似文献
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Chiral high-performance liquid chromatography (HPLC) separation of lignans with semi-micro columns of 1.0–2.0mm inner diameter (i.d.) was established for the first time. Practical sensitivity was increased 5 to 20-fold compared with that of conventional chiral HPLC using analytical columns with 4.6mm i.d. The semi-micro chiral HPLC system can be applied to high-sensitivity enantiomeric separation of many chiral organic compounds in addition to lignans. 相似文献
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Katja Mustonen Anneli Niemi Marja Raekallio Mari Heinonen Olli AT Peltoniemi Mari Palviainen Mia Siven Marikki Peltoniemi Outi Vainio 《Acta veterinaria Scandinavica》2012,54(1):55
Background
Ketoprofen is a non-steroidal anti-inflammatory drug which has been widely used for domestic animals. Orally administered racemic ketoprofen has been reported to be absorbed well in pigs, and bioavailability was almost complete. The objectives of this study were to analyze R- and S-ketoprofen concentrations in plasma after oral (PO) and intra muscular (IM) routes of administration, and to assess the relative bioavailability of racemic ketoprofen for both enantiomers between those routes of administration in growing pigs.Methods
Eleven pigs received racemic ketoprofen at dose rates of 4 mg/kg PO and 3 mg/kg IM in a randomized, crossover design with a 6-day washout period. Enantiomers were separated on a chiral column and their concentrations were determined by liquid chromatography-tandem mass spectrometry. Pharmacokinetic parameters were calculated and relative bioavailability (Frel) was determined for S and R –ketoprofen.Results
S-ketoprofen was the predominant enantiomer in pig plasma after administration of the racemic mixture via both routes. The mean (± SD) maximum S-ketoprofen concentration in plasma (7.42 mg/L ± 2.35 in PO and 7.32 mg/L ± 0.75 in IM) was more than twice as high as that of R-ketoprofen (2.55 mg/L ± 0.99 in PO and 3.23 mg/L ± 0.70 in IM), and the terminal half-life was three times longer for S-ketoprofen (3.40 h ± 0.91 in PO and 2.89 h ± 0.85 in IM) than R-ketoprofen (1.1 h ± 0.90 in PO and 0.75 h ± 0.48 in IM). The mean (± SD) relative bioavailability (PO compared to IM) was 83 ± 20% and 63 ± 23% for S-ketoprofen and R-ketoprofen, respectively.Conclusions
Although some minor differences were detected in the ketoprofen enantiomer concentrations in plasma after PO and IM administration, they are probably not relevant in clinical use. Thus, the pharmacological effects of racemic ketoprofen should be comparable after intramuscular and oral routes of administration in growing pigs. 相似文献5.
Fumio Kawamura Yoshinari Kikuchi Tatsuro Ohira Mitsuyoshi Yastagai 《Journal of Wood Science》2000,46(2):167-171
The phenolic constituents of the roots ofTaxus cuspidata (Japanese yew) were investigated. Four lignans, [(+)-taxiresinol (1), (+)-lariciresinol (2), (–)-secoisolariciresinol (3), and (+)-pinoresinol (4)] were isolated and identified. The assignment of proton and carbon atoms for the lignans were finally solved by one- and twodimensional-nuclear magnetic resonance spectra. The enantiomeric excess of these lignans were determined by chiral high-performance liquid Chromatographic analyses. (+)-Lariciresinol and (–)-secoisolariciresinol were optically pure; (+)-taxiresinol was also suggested to be optically pure, although (+)-pinoresinol was not (77% enantiomeric excess). 相似文献
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