In vivo sampling for pharmacokinetic studies in small experimental animals: a combination of microdialysis, planar chromatography and digital autoradiography.
OBJECTIVE
We describe a method for measuring the pharmacokinetics of positron emission tomography (PET) tracers during rat studies using microdialysis (MD) in combination with planar chromatography and digital autoradiography with a phosphoimager plate (DAR).


METHODS
An MD probe was inserted into the jugular vein of the rat and perfused with physiological buffer solution (n>/=3). An (18)F-labeled radiopharmaceutical was injected intravenously, and dialysate fractions were collected, measured for radioactivity, and applied on a chromatography plate. This plate was exposed with an imaging plate for radioactivity imaging.


RESULTS
Time activity curves for unbound, unchanged tracer and metabolites were determined. The amount of unchanged tracer in the last MD fraction was compared with the amount in the plasma sample collected after sacrifice of the animal.


CONCLUSIONS
MD continuously samples and monitors the amount of unbound tracer in the blood from one single experimental animal. MD combined with planar chromatography and DAR is a highly sensitive and linear method for simultaneous analysis of PET tracers and their metabolites in blood.
Haaparanta
Merja
M
Turku PET Centre, Medicity Research Laboratory/PET, Turku, Finland. mehaaso@utu.fi
Grönroos
Tove
T
Marjamäki
Päivi
P
Eskola
Olli
O
Bergman
Jörgen
J
Paul
Robert
R
Solin
Olof
O
D000818:Animals; D001345:Autoradiography; D002845:Chromatography; D005462:Fluorine Radioisotopes / Q000493:pharmacokinetics*; D008297:Male; D017551:Microdialysis; D011856:Radiographic Image Enhancement; D051381:Rats / Q000378:metabolism*; D017207:Rats, Sprague-Dawley; D014055:Tomography, Emission-Computed
D005462:Fluorine Radioisotopes