Linked Life Data

16364587

Source:http://linkedlifedata.com/resource/pubmed/id/16364587

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2006-3-20
pubmed:abstractText
During in vivo microdialysis studies time-consuming and laborious bedside calibration methods, e.g. retrodialysis, have to be performed. To reduce the burden on the patient it would be desirable to establish a reliable, time-saving calibration technique to obtain the in vivo recovery describing the relative drug transfer across the membrane of the microdialysis probe. The performed study aimed to evaluate and validate the use of urea as an endogenous reference compound to determine relative in vivo recovery of anti-infectives, e.g. linezolid used herein as model drug. In order to meet the special requirements imposed by microdialysis to measure urea concentrations in very small sample volumes ( approximately 10 microL) a photometric assay in 96-well microtiter plates was established based on the method of Berthelot. Subsequently, concentration- and flow rate-dependence were evaluated in vitro to determine the relative recovery (RR) of urea. Finally, urea and linezolid concentrations in human microdialysis samples were measured. The developed assay was validated according to international guidelines and met all requirements. Relative in vitro recovery was found to be independent from concentration and dependent on flow rate. Subsequently, relative in vivo recovery of urea was correlated with relative in vivo recovery of linezolid obtained by the traditional retrodialysis method. In healthy volunteers, the mean ratio of the relative recovery of linezolid to the relative recovery of urea was 0.6 for the subcutaneous (s.c.: CV 33.4%, n = 48) and 0.7 for the intramuscular probe (i.m.: CV 18.8%, n = 40), respectively. In critically ill patients this ratio was 0.7 for both tissues (s.c.: CV 32.8%, n = 18; i.m.: CV 22.1%, n = 17). Successful calibration of the urea reference technique without the need to use in vitro data will further promote the application of microdialysis in clinical studies especially in critically ill patients, as it reduces the imposed burden to a minimum.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0731-7085
pubmed:author
pubmed:issnType
Print
pubmed:day
11
pubmed:volume
41
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
233-9
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Urea as an endogenous surrogate in human microdialysis to determine relative recovery of drugs: analytics and applications.
pubmed:affiliation
Department of Clinical Pharmacy, Institute of Pharmacy, Freie Universitaet Berlin, Kelchstr. 31, D-12169 Berlin, Germany.
pubmed:publicationType
Journal Article