Document Detail


Biliary excretion of 17-(allylamino)-17-demethoxygeldanamycin (NSC 330507) and metabolites by Fischer 344 rats.
MedLine Citation:
PMID:  12761648     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
PURPOSE: 17-(Allylamino)-17-demethoxygeldanamycin (17AAG), an analogue of the benzoquinone ansamycin geldanamycin, has been extensively studied preclinically and is being evaluated clinically. Studies were performed to define the biliary excretion of 17AAG after i.v. delivery to rats, and to characterize the metabolites of 17AAG observed in rat bile. MATERIALS AND METHODS: In vivo studies were performed in bile-duct-cannulated Fischer 344 rats given a 10 mg/kg i.v. bolus dose of 17AAG. In vitro studies were performed with cloned human CYPs and microsomal epoxide hydrolase. Biliary excretion of 17AAG and metabolites was quantified by HPLC and followed for 4 h after drug delivery. 17AAG metabolites in bile and in in vitro reaction mixtures were identified with LC/MS/MS. RESULTS: By 15 min after i.v. delivery of 17AAG, bile contained at least 15 biotransformation products with absorbance spectra similar to that of 17AAG. Of these, metabolites eluting at 2.7, 2.9, and 8.6 min were present in sufficient concentrations to be quantified, although the lack of authentic standards resulted in their being expressed as 17AAG equivalents. Within the first 4 h after drug delivery, biliary excretion accounted for 28.9+/-6.1% of the 10-mg/kg 17AAG dose. 17AAG and 17-(amino)-17-demethoxygeldanamycin (17AG) accounted for 4.1+/-1.0% of the delivered dose, with 17AAG accounting for 2.0+/-0.5% and 17AG accounting for 2.1+/-0.5%. The metabolites eluting at 2.7, 2.9, and 8.6 min accounted for 10.6+/-2.0%, 9.8+/-1.2%, and 1.0+/-0.2%, respectively, of the administered dose. LC/MS/MS analysis of bile demonstrated major metabolites with molecular weights of 545 and 619, corresponding to 17AG and the diol previously described as resulting from metabolism of 17AAG by CYP3A and microsomal epoxide hydrolase. Of the remaining proposed metabolites, ten had a mass and MS/MS spectrum consistent with mono-oxygenated 17AAG metabolites. One of these metabolites has been identified as the epoxide previously described as resulting from CYP3A oxidation of the allyl double bond. Two other proposed metabolites had a mass and MS/MS spectrum consistent with demethylated 17AAG metabolites, and one had a mass and MS/MS spectrum consistent with a di-demethylated 17AAG metabolite. An analogous series of demethylated and oxidized metabolites was also observed for the 17AG metabolite. CONCLUSIONS: Biliary excretion of 17AAG represents a major route of elimination, although most of the material excreted is in the form of metabolites. Bile of rats dosed with 17AAG contained a number of metabolites not previously identified in the plasma or urine of mice treated with 17AAG, but analogous to metabolites described in bile of rats treated with 17-(dimethylaminoethylamino)-17-demethoxygeldanamycin (17DMAG, NSC 707545), another geldanamycin analogue undergoing preclinical evaluation in preparation for subsequent clinical trials.
Authors:
Steven M Musser; Merrill J Egorin; Eleanor G Zuhowski; Deborah R Hamburger; Robert A Parise; Joseph M Covey; Kevin D White; Julie L Eiseman
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.     Date:  2003-05-22
Journal Detail:
Title:  Cancer chemotherapy and pharmacology     Volume:  52     ISSN:  0344-5704     ISO Abbreviation:  Cancer Chemother. Pharmacol.     Publication Date:  2003 Aug 
Date Detail:
Created Date:  2003-07-28     Completed Date:  2003-09-30     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  7806519     Medline TA:  Cancer Chemother Pharmacol     Country:  Germany    
Other Details:
Languages:  eng     Pagination:  139-46     Citation Subset:  IM    
Affiliation:
Instrumentation and Biophysics Branch, Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD 20740, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Antibiotics, Antineoplastic / chemistry,  metabolism*
Benzoquinones
Bile / metabolism*
Biotransformation
Chromatography, High Pressure Liquid
Cytochrome P-450 Enzyme System / chemistry
Epoxide Hydrolases / chemistry
Humans
Lactams, Macrocyclic
Male
Mass Spectrometry
Oxidation-Reduction
Rats
Rats, Inbred F344
Rifabutin / analogs & derivatives*,  chemistry,  metabolism*
Grant Support
ID/Acronym/Agency:
2P30CA47904/CA/NCI NIH HHS; N01-CM07106/CM/NCI NIH HHS
Chemical
Reg. No./Substance:
0/17-(allylamino)-17-demethoxygeldanamycin; 0/Antibiotics, Antineoplastic; 0/Benzoquinones; 0/Lactams, Macrocyclic; 72559-06-9/Rifabutin; 9035-51-2/Cytochrome P-450 Enzyme System; EC 1.14.14.1/CYP3A protein, human; EC 3.3.2.-/Epoxide Hydrolases

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


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