Linked Life Data

1686232

Source:http://linkedlifedata.com/resource/pubmed/id/1686232

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1992-3-24
pubmed:abstractText
Felodipine, a 1,4-dihydropyridine derivative, is a potent, vasoselective calcium antagonist that is used clinically as a racemic mixture of two stereoisomers. In the rat, dog, and human, the bioavailability of an oral dose is about 15% because of high first-pass metabolism. Oxidation of the dihydropyridine ring to the corresponding achiral, pharmacologically inactive pyridine metabolite is the predominant metabolic step. In the liver, this metabolism is catalyzed by cytochrome P-450. In the present study, the metabolism of (R)- and (S)- felodipine was compared in vitro in liver microsomes from rats, dogs, and humans. Slightly higher rates of metabolism were found for the (S)-enantiomer in rat and dog liver microsomes. However, no significant differences were observed in the Michaelis-Menten parameters, Vmax or KM. In human liver microsomes, the (R)-enantiomer was metabolized more readily than (S)-felodipine. The mean value of KM was lower for (R)-felodipine, while the Vmax values of the enantiomers were similar. The intrinsic clearance, defined as the ratio of Vmax and KM, was about two times higher for (R)-felodipine. Assuming complete absorption and that the bioavailability is determined by the first-pass metabolism in the liver, these in vitro results suggest that the bioavailability of (S)-felodipine in vivo is about two times higher than that of (R)-felodipine.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0090-9556
pubmed:author
pubmed:issnType
Print
pubmed:volume
19
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
889-94
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:articleTitle
Stereoselective metabolism of felodipine in liver microsomes from rat, dog, and human.
pubmed:affiliation
Hässle Research Laboratories, Mölndal, Sweden.
pubmed:publicationType
Journal Article, Comparative Study, In Vitro