The design and validation of a novel intravenous microdialysis probe: application to fluconazole pharmacokinetics in the freely-moving rat model.
OBJECTIVE
The purpose of this study was to design and validate a concentric, flexible intravenous microdialysis probe to determine drug concentrations in blood from the inferior vena cava of a freely-moving animal model.


METHODS
An intravenous microdialysis probe was constructed using fused-silica tubing and an acrylonitrile/sodium methallyl sulfonate copolymer hollow fiber. The probe was tested in vitro for the recovery of fluconazole and UK-54,373, a fluconazole analog used for probe calibration by retrodialysis. Subsequent in vivo validation was done in rats (n = 7) that had a microdialysis probe inserted into the inferior vena cava via the femoral vein, and the femoral artery was cannulated for simultaneous blood sampling. Comparisons of fluconazole pharmacokinetic parameters resulting from the two sampling methods were performed at 2 and 10 days after probe implantation.


RESULTS
There were no statistical differences between the microdialysis sampling and conventional blood sampling methods for the T1/2, Cl, Vdss, and dose-normalized AUC by paired t-test (p > 0.05) for repeated dosing at day 2 and day 10 after probe placement. The probe recovery, as determined by retrodialysis, significantly decreased over the ten day period. This finding indicates the necessity for frequent recovery determinations during a long-term blood microdialysis experiment.


CONCLUSIONS
These results show that microdialysis sampling in the inferior vena cava using this unique and robust probe design provides an accurate method of determining blood pharmacokinetics in the freely-moving rat for extended experimental periods. The probe design allows for a simple surgical placement into the inferior vena cava which results in a more stable animal preparation for long-term sampling and repeated-measures experimental designs.
Yang
H
H
Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha 68198-6025, USA.
Wang
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Q
Elmquist
W F
WF
D000818:Animals; D019540:Area Under Curve; D001798:Blood Proteins / Q000378:metabolism; D001800:Blood Specimen Collection / Q000295:instrumentation*; D004867:Equipment Design; D015725:Fluconazole / Q000097:blood / Q000493:pharmacokinetics*; D008297:Male; D017551:Microdialysis / Q000295:instrumentation*; D011485:Protein Binding; D051381:Rats; D017207:Rats, Sprague-Dawley; D015203:Reproducibility of Results; D014230:Triazoles / Q000097:blood; D014682:Vena Cava, Inferior
D001798:Blood Proteins; D014230:Triazoles; C104780:UK 54373; D015725:Fluconazole