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Updated: Feb 13, 2026
08:09
Methionine Functionalized Biocompatible Block Copolymers for Targeted Plasmid DNA Delivery
Published on: August 6, 2019
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Improving the stability of 11C-labeled L-methionine with ascorbate
Michael Woods1, Leo Leung1, Kari Frantzen1
11Department of Functional Imaging, BC Cancer Agency, Vancouver, BC Canada.
EJNMMI Radiopharmacy and Chemistry
|March 6, 2018
Summary
Carbon-11 L-methionine (11C-MET) brain tumor imaging tracer can degrade. Adding ascorbate to the formulation stabilizes 11C-MET, preventing degradation for up to one hour post-synthesis.
Area of Science:
- Radiochemistry
- Nuclear Medicine
- Biochemistry
Background:
- Carbon-11 L-methionine (11C-MET) is a PET imaging tracer for brain tumors.
- The stability of 11C-MET in clinical formulations is not well-documented.
- Fast degradation of HPLC-purified 11C-MET was recently observed.
Purpose of the Study:
- To investigate the cause of 11C-MET degradation.
- To identify methods for stabilizing 11C-MET formulations.
- To ensure the quality of 11C-MET for clinical use.
Main Methods:
- HPLC purification of 11C-MET.
- Identification of the degradation product.
- Addition of ascorbate to the HPLC eluant and formulation.
- Stability testing of the final 11C-MET formulation.
Main Results:
- The degradation product was identified as 11C-labeled methionine sulfoxide (11C-METSO).
- Adding ascorbate (100 ppm) to the HPLC eluant prevented degradation.
- HPLC-purified 11C-MET remained stable for up to 1 hour post-synthesis when formulated with ascorbate.
Conclusions:
- Ascorbate addition minimizes 11C-MET degradation.
- Ascorbate is recommended for 11C-MET formulation solutions, especially for delayed patient administration.
- Ensuring 11C-MET stability is crucial for accurate PET imaging of brain tumors.
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