Document Detail


Biotransformation of topotecan in the isolated perfused rat liver: identification of three novel metabolites.
MedLine Citation:
PMID:  9703931     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
This study evaluates the metabolism of the anticancer drug topotecan (TPT) in the isolated perfused rat liver of male Wistar-rats. Using a sensitive high-performance liquid chromatography method, in bile TPT, its ring-opened hydroxycarboxylate form and three new metabolites could be quantified. Enzymatic hydrolysis of the metabolites with beta-glucuronidase and mass spectroscopy revealed the existence of glucuronidated TPT as well as unconjugated and glucuronidated bidesmethyl TPT. Biliary secretion of glucuronidated N-bidesmethyl TPT was fast reaching a maximum already after 15 min(30.6 +/- 15.1 pmol/g liver.min), whereas secretion of TPT, topotecan glucuronide and N-bidesmethyl TPT was delayed (maximum at 30 min: 431 +/- 19, 6.4 +/- 2.1 and 12.7 +/- 2.7 pmol/g liver.min, respectively). No release of TPT metabolites into the perfusate was detected. The amount of TPT, TPT glucuronide, N-bidesmethyl TPT and N-bidesmethyl TPT glucuronide excreted into bile during 60 min of perfusion was 2.10 +/- 0.483%, 0.031 +/- 0.006%, 0.058 +/- 0.013% and 0.108 +/- 0.012% of TPT cleared from the perfusate over 60 min, respectively. In conclusion we could identify three novel TPT metabolites, however, their overall metabolism in the rat liver is low.
Authors:
P Platzer; S Schaden; T Thalhammer; G Hamilton; B Rosenberg; I Silgoner; W Jäger
Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Anticancer research     Volume:  18     ISSN:  0250-7005     ISO Abbreviation:  Anticancer Res.     Publication Date:    1998 Jul-Aug
Date Detail:
Created Date:  1998-09-01     Completed Date:  1998-09-01     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8102988     Medline TA:  Anticancer Res     Country:  GREECE    
Other Details:
Languages:  eng     Pagination:  2695-700     Citation Subset:  IM    
Affiliation:
Institute of Pharmaceutical Chemistry, University of Vienna, Austria.
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MeSH Terms
Descriptor/Qualifier:
Animals
Bile / chemistry,  metabolism
Biotransformation
Chromatography, High Pressure Liquid
Glucuronates / analysis
Kinetics
Liver / metabolism*
Male
Molecular Structure
Perfusion
Rats
Rats, Wistar
Sensitivity and Specificity
Time Factors
Topotecan / pharmacokinetics*
Chemical
Reg. No./Substance:
0/Glucuronates; 123948-87-8/Topotecan

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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