Document Detail

The role of drug metabolism in drug discovery: a case study in the selection of an oxytocin receptor antagonist for development.
MedLine Citation:
PMID:  7569665     Owner:  NLM     Status:  MEDLINE    
Drug discovery is a process involving multiple disciplines and interests. During the research phase of drug discovery, usually a large number of compounds are evaluated for biological activity and toxicological potential in animal species. Various types of problems with respect to pharmacodynamics, pharmacokinetics, and toxicity are commonly encountered at this stage. Drug metabolism, as a discipline participating in a drug discovery team, can play an important role in identifying factors underlying the problems, facilitate the optimal selection of compounds for further development, provide information on metabolites for possible improvement in drug design, and contribute to the identification of the appropriate animal species for subsequent toxicity testing. During the process of evaluating oxytocin receptor antagonists for further development for treatment of preterm labor, in vivo and in vitro drug metabolism studies conducted in rats, dogs, and monkeys contributed to the selection of L-368,899 as the development candidate on the basis of pharmacokinetic and metabolism observations. The presence of active N-demethylated metabolites of two other equipotent compounds in rats and dogs was found to be the major factor responsible for the discrepancy between oral bioavailability and efficacies observed for these 2 compounds. For L-368,899, a compound that demonstrated 20-40% oral bioavailability in rats, dogs, and chimpanzees, extensive first-pass metabolism rather than absorption was determined as the major factor responsible for the poor bioavailability (< 1%) in rhesus monkeys. In vitro metabolism studies with hepatic microsomes from rats, dogs, monkeys, and humans substantiated the conclusion that the rate of hepatic metabolism of L-368,899 in monkeys is faster than in the other species.
S H Chiu; K A Thompson; S H Vincent; R F Alvaro; S W Huskey; R A Stearns; D J Pettibone
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Publication Detail:
Type:  Journal Article; Review    
Journal Detail:
Title:  Toxicologic pathology     Volume:  23     ISSN:  0192-6233     ISO Abbreviation:  Toxicol Pathol     Publication Date:    1995 Mar-Apr
Date Detail:
Created Date:  1995-11-22     Completed Date:  1995-11-22     Revised Date:  2009-07-01    
Medline Journal Info:
Nlm Unique ID:  7905907     Medline TA:  Toxicol Pathol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  124-30     Citation Subset:  IM    
Department of Drug Metabolism, Merck Research Laboratories, Rahway, New Jersey 07065, USA.
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MeSH Terms
Bornanes / pharmacokinetics
Chemistry, Pharmaceutical
Macaca mulatta
Pharmaceutical Preparations / metabolism*
Piperazines / pharmacokinetics
Rats, Sprague-Dawley
Receptors, Oxytocin / antagonists & inhibitors*
Tocolytic Agents / pharmacokinetics
Reg. No./Substance:
0/Bornanes; 0/Pharmaceutical Preparations; 0/Piperazines; 0/Receptors, Oxytocin; 0/Tocolytic Agents; 148927-60-0/L 368899

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

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