Document Detail


Impulse-response studies on tracer doses of [14C]lignocaine and its multiple metabolites in the perfused rat liver.
MedLine Citation:
PMID:  9364412     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The outflow-concentration-time profiles for lignocaine (lidocaine) and its metabolites have been measured after bolus impulse administration of [14C]lignocaine into the perfused rat liver. Livers from female Sprague-Dawley rats were perfused in a once-through fashion with red-blood-cell-free Krebs-Henseleit buffer containing 0 or 2% bovine serum albumin. Perfusate flow rates of 20 and 30 mL min-1 were used and both normal and retrograde flow directions were employed. Significant amounts of metabolite were detected in the effluent perfusate soon after lignocaine injection. The early appearance of metabolite contributed to bimodal outflow profiles observed for total 14C radioactivity. The lignocaine outflow profiles were well characterized by the two-compartment dispersion model, with efflux rate << influx rate. The profiles for lignocaine metabolites were also characterized in terms of a simplified two-compartment dispersion model. Lignocaine was found to be extensively metabolized under the experimental conditions with the hepatic availability ranging between 0.09 and 0.18. Generally lignocaine and metabolite availability showed no significant change with alterations in perfusate flow rate from 20 to 30 mL min-1 or protein content from 0 to 2%. A significant increase in lignocaine availability occurred when 1200 microM unlabelled lignocaine was added to the perfusate. Solute mean transit times generally decreased with increasing flow rate and with increasing perfusate protein content. The results confirm that lignocaine pharmacokinetics in the liver closely follow the predictions of the wellstirred model. The increase in lignocaine availability when 1200 microM unlabelled lignocaine was added to the perfusate is consistent with saturation of the hydroxylation metabolic pathways of lignocaine metabolism.
Authors:
G D Mellick; M S Roberts
Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of pharmacy and pharmacology     Volume:  49     ISSN:  0022-3573     ISO Abbreviation:  J. Pharm. Pharmacol.     Publication Date:  1997 Oct 
Date Detail:
Created Date:  1998-02-11     Completed Date:  1998-02-11     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0376363     Medline TA:  J Pharm Pharmacol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  1008-18     Citation Subset:  IM    
Affiliation:
University of Queensland, Department of Medicine, Princess Alexandra Hospital, Australia.
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MeSH Terms
Descriptor/Qualifier:
Anesthetics, Local / pharmacokinetics*
Animals
Area Under Curve
Biological Availability
Biotransformation
Chromatography, High Pressure Liquid
Female
Hydroxylation
Lidocaine / pharmacokinetics*
Liver / metabolism*
Models, Biological
Rats
Rats, Sprague-Dawley
Chemical
Reg. No./Substance:
0/Anesthetics, Local; 137-58-6/Lidocaine

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


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