Noninvasive measurement of pharmacokinetics by near-infrared fluorescence imaging in the eye of mice.
OBJECTIVE
For generating preclinical pharmacokinetics (PKs) of compounds, blood is drawn at different time points and levels are quantified by different analytical methods. In order to receive statistically meaningful data, 3 to 5 animals are used for each time point to get serum peak-level and half-life of the compound. Both characteristics are determined by data interpolation, which may influence the accuracy of these values. We provide a method that allows continuous monitoring of blood levels noninvasively by measuring the fluorescence intensity of labeled compounds in the eye and other body regions of anesthetized mice.


METHODS
The method evaluation was performed with four different fluorescent compounds: (i) indocyanine green, a nontargeting dye; (ii) OsteoSense750, a bone targeting agent; (iii) tumor targeting Trastuzumab-Alexa750; and (iv) its F(ab')2-alxea750 fragment. The latter was used for a direct comparison between fluorescence imaging and classical blood analysis using enzyme-linked immunosorbent assay (ELISA).


RESULTS
We found an excellent correlation between blood levels measured by noninvasive eye imaging with the results generated by classical methods. A strong correlation between eye imaging and ELISA was demonstrated for the F(ab')2 fragment. Whole body imaging revealed a compound accumulation in the expected regions (e.g., liver, bone).


CONCLUSIONS
The combination of eye and whole body fluorescence imaging enables the simultaneous measurement of blood PKs and biodistribution of fluorescent-labeled compounds.
Pharma Research and Early Development (pRED), Discovery Oncology, Roche Diagnostics GmbH, Nonnenwald 2, D-82377 Penzberg, Germany.
Michael
M
Dobosz
Pharma Research and Early Development (pRED), Discovery Oncology, Roche Diagnostics GmbH, Nonnenwald 2, D-82377 Penzberg, Germany.
Steffen
S
Strobel
Large Molecule Research (LMR), Roche Diagnostics GmbH, Nonnenwald 2, D-82377 Penzberg, Germany.
Kay-Gunnar
KG
Stubenrauch
Pharma Research and Early Development (pRED), Discovery Oncology, Roche Diagnostics GmbH, Nonnenwald 2, D-82377 Penzberg, Germany.
Franz
F
Osl
Pharma Research and Early Development (pRED), Discovery Oncology, Roche Diagnostics GmbH, Nonnenwald 2, D-82377 Penzberg, Germany.
Werner
W
Scheuer
D000818:Animals; D061067:Antibodies, Monoclonal, Humanized / Q000737:chemistry; D002138:Calibration; D004797:Enzyme-Linked Immunosorbent Assay; D005123:Eye / Q000473:pathology*; D005260:Female; D005453:Fluorescence; D007128:Immunoglobulin Fragments / Q000737:chemistry; D007208:Indocyanine Green / Q000737:chemistry; D007700:Kinetics; D051379:Mice; D016513:Mice, SCID; D008856:Microscopy, Fluorescence / Q000295:instrumentation / Q000379:methods*; D015203:Reproducibility of Results; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D013388:Succinimides / Q000737:chemistry; D000068878:Trastuzumab
C502599:Alexa Fluor 750; D061067:Antibodies, Monoclonal, Humanized; D007128:Immunoglobulin Fragments; D013388:Succinimides; D007208:Indocyanine Green; D000068878:Trastuzumab