The Label Matters: μPET Imaging of the Biodistribution of Low Molar Mass 89Zr and 18F-Labeled Poly(2-ethyl-2-oxazoline)

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• 作者：Mathias GlassnerLuca Palmieri ; Bryn D. Monnery ; Thomas Verbrugghen ; Steven Deleye ; Sigrid Stroobants ; Steven Staelens ; Leonie wyffels ; Richard Hoogenboom
• 刊名：Biomacromolecules
• 出版年：2017
• 出版时间：January 9, 2017
• 年：2017
• 卷：18
• 期：1
• 页码：96-102
• 全文大小：476K
• ISSN：1526-4602

文摘

Poly(2-alkyl-2-oxazoline)s (PAOx) have received increasing interest for biomedical applications. Therefore, it is of fundamental importance to gain an in-depth understanding of the biodistribution profile of PAOx. We report the biodistribution of poly(2-ethyl-2-oxazoline) (PEtOx) with a molar mass of 5 kDa radiolabeled with PET isotopes ⁸⁹Zr and ¹⁸F. ¹⁸F-labeled PEtOx is prepared by the strain-promoted azide–alkyne cycloaddition (SPAAC) of [¹⁸F]fluoroethylazide to bicyclo[6.1.0]non-4-yne (BCN)-functionalized PEtOx as many common labeling strategies were found to be unsuccessful for PEtOx. ⁸⁹Zr-labeled PEtOx is prepared using desferrioxamine end-groups as a chelator. Five kDa PEtOx shows a significantly faster blood clearance compared to PEtOx of higher molar mass while uptake in the liver is lower, indicating a minor contribution of the liver in excretion of the 5 kDa PEtOx. While [¹⁸F]-PEtOx displays a rapid and efficient clearance from the kidneys, 5 kDa [⁸⁹Zr]-Df-PEtOx is not efficiently cleared over the time course of the study, which is most likely caused by trapping of ⁸⁹Zr-labeled metabolites in the renal tubules and not the polymer itself, demonstrating the importance of selecting the appropriate label for biodistribution studies.