Document Detail


Pharmacokinetics of camptothecins administered orally.
MedLine Citation:
PMID:  8993508     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The equilibrium between lactone and salt forms of camptothecin (CPT) and its derivatives including 9-nitrocamptothecin (9-NC) depends on pH, binding to albumin and other factors. Their antitumor activity is associated with the lactone form. Our goal was the development of dosing regimens optimal for chemotherapeutic activity of the drug. The effect of p.o., i.v. and i.m. administration on the tumor uptake of [3H]-CPT or [3H]-9-NC in tumor-bearing nude mice was studied by whole-body autoradiography. In all cases, [3H]-CPT or [3H]-9-NC accumulated mainly in the gastrointestinal tract. Comparatively lower levels of drug were detected in liver, kidney, tumor, and other sites. Consistently high tumor/blood ratios following oral administration of drug suggest this route as the most effective way of treatment. Within 4 h of i.s. administration of 2 mg/kg CPT or 1 mg/kg 9-NC to mice, lactone forms were 57-81% and 47-95% of total plasma drug levels, respectively. However in plasma of humans treated p.o. with varying doses of CPT or 9-NC, lactone forms were only a minor component of total drug levels. It is concluded that ratios of lactone/total drug are much higher in mice than in humans, which influence the therapeutic efficacies these drugs in the two species.
Authors:
J G Liehr; A E Ahmed; B C Giovanella
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Review    
Journal Detail:
Title:  Annals of the New York Academy of Sciences     Volume:  803     ISSN:  0077-8923     ISO Abbreviation:  Ann. N. Y. Acad. Sci.     Publication Date:  1996 Dec 
Date Detail:
Created Date:  1997-01-29     Completed Date:  1997-01-29     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7506858     Medline TA:  Ann N Y Acad Sci     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  157-63     Citation Subset:  IM    
Affiliation:
Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston 77555-1031, USA.
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MeSH Terms
Descriptor/Qualifier:
Administration, Oral
Animals
Antineoplastic Agents, Phytogenic / administration & dosage,  pharmacokinetics*
Camptothecin / administration & dosage,  analogs & derivatives,  blood,  pharmacokinetics*
Enzyme Inhibitors / administration & dosage,  pharmacokinetics*
Humans
Lactones / blood
Mice
Mice, Nude
Chemical
Reg. No./Substance:
0/Antineoplastic Agents, Phytogenic; 0/Enzyme Inhibitors; 0/Lactones; 7689-03-4/Camptothecin

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


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