Pharmacokinetic studies with the lipid‐regulating agent beclobrate: Enantiospecific assay for beclobric acid using a new fluorescent chiral coupling component (S‐FLOPA)
作者:
Sascha Mayer,
Ernst Mutschler,
Hildegard Spahn‐Langguth,
期刊:
Chirality
(WILEY Available online 1991)
卷期:
Volume 3,
issue 1
页码: 35-42
ISSN:0899-0042
年代: 1991
DOI:10.1002/chir.530030108
出版商: Wiley‐Liss, Inc.
关键词: chiral derivatization;pharmacokinetics;enantiospecific assay;fluorescent derivatization;flunoxaprofen;acyl glucuronides
数据来源: WILEY
摘要:
AbstractThe major biotransformation pathway for the chiral lipid‐regulating agent beclobrate is conversion to the corresponding carboxylic acid, which is then metabolized to the acyl glucuronide. An enantiospecific assay for biological material was developed that is based on chiral derivatization withN‐ethyl‐N′‐(3‐dimethylaminopropyl)carbodiimide (EDAC) and the primary amine S‐FLOPA, a new chiral coupling component for carboxylic acids derived from the 2‐arylpropionic acid S‐flunoxaprofen. Conversion of beclobric acid to the acyl chloride prior to coupling with the amine is also feasible. From plasma or urine beclobric acid was extracted inton‐hexane/ethanol (9:1) at pH 4 after addition of sodium chloride. Clofibric acid was used as internal standard. Derivatization with EDAC/FLOPA was performed under addition of 1‐hydroxybenzotriazole in anhydrous dichloromethane containing trace amounts of pyridine (ambient temperature/2 h reaction time). The chromatographic separation was performed on a silica gel stationary phase (Zorbax Sil) usingn‐hexane–chloroform–ethanol (100:10: 0.75, by vol) as mobile phase [flow rate, 2 ml/min; fluorescence detection, 305/355 nm; elution order of the derivatives, (−) before (+)]. Coefficients of variation were between 1.3 and 9.3% for both plasma and urine. Limit of quantification was 20–25 ng/ml for plasma based on a sample volume of 0.2 ml. Application of the assay in a pilot pharmacokinetic study showed significant differences between the kinetics of the two enantiomers. In plasma and urine, the concentrations of the dextrorotatory enantiomer exceeded those of the levoro
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