Abstract
The tissue distribution of two 14C drugs were quantitatively compared using the techniques of whole body autoradioluminography (WBAL) and radiometry. Quantitative analysis of tissue radioactivity in whole body cryosections was accomplished from storage phosphor images using the MicroComputer Imaging Device. After obtaining whole body sections from four frozen rats and three frozen ferrets, each WBAL-sectioned specimen was partially thawed before obtaining tissue samples for radiometric analysis. For all tissues examined, concentrations of radioactivity determined by WBAL were comparable with those determined by dissection and liquid scintillation analysis (DLSA), except for renal tissue obtained from different kidneys of the same ferret and for rat ocular tissues. A 2-fold difference was observed between WBAL and DLSA evaluations of radioactivity in the contralateral kidneys of one ferret. DLSA evaluation only provided an assessment of total radioactivity in the eye, whereas WBAL evaluation determined the selective distribution of radioactivity to ocular tissues. Resolution in DLSA evaluation of ocular tissues was restricted by limitations of the dissection procedure. These results indicated that the quantitation of tissue radioactivity by WBAL was as precise as DLSA evaluation, and WBAL also provided results to the quantitative distribution of radioactivity to localized sites in organs not feasible by DLSA.
Footnotes
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Send reprint requests to: Michael J. Potchoiba, Department of Drug Metabolism, Central Research, Pfizer Inc., Eastern Point Road, Groton, CT 06340.
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This study was presented during a poster session at the 1995 American Association of Pharmaceutical Scientists meeting (Abstract PPDM 8210).
- Abbreviations used are::
- DLSA
- dissection and liquid scintillation analysis
- WBA
- whole body autoradiography
- CQCS
- cryosection quality control samples
- STD
- standard curve calibrators
- QCS
- quality control samples
- WBAL
- whole body autoradioluminography
- Received July 3, 1997.
- Accepted November 24, 1997.
- The American Society for Pharmacology and Experimental Therapeutics
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