NMR‐based approach to the analysis of radiopharmaceuticals: radiochemical purity,specific activity,and radioactive concentration values by proton and tritium NMR spectroscopy |
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| Authors: | David J. Schenk Peter G. Dormer David Hesk Scott R. Pollack Carolee Flader Lavey |
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| Affiliation: | Process and Analytical Chemistry, Merck Research Laboratories, Rahway, NJ, USA |
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| Abstract: | Compounds containing tritium are widely used across the drug discovery and development landscape. These materials are widely utilized because they can be efficiently synthesized and produced at high specific activity. Results from internally calibrated 3H and 1H nuclear magnetic resonance (NMR) spectroscopy suggests that at least in some cases, this calibrated approach could supplement or potentially replace radio‐high‐performance liquid chromatography for radiochemical purity, dilution and scintillation counting for the measurement of radioactivity per volume, and liquid chromatography/mass spectrometry analysis for the determination of specific activity. In summary, the NMR‐derived values agreed with those from the standard approaches to within 1% to 9% for solution count and specific activity. Additionally, the NMR‐derived values for radiochemical purity deviated by less than 5%. A benefit of this method is that these values may be calculated at the same time that 3H NMR analysis provides the location and distribution of tritium atoms within the molecule. Presented and discussed here is the application of this method, advantages and disadvantages of the approach, and a rationale for utilizing internally calibrated 1H and 3H NMR spectroscopy for specific activity, radioactive concentration, and radiochemical purity whenever acquiring 3H NMR for tritium location. |
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| Keywords: | tritium label 3H 3H‐NMR q‐NMR quantitative NMR radioactive concentration radio‐HPLC radiochemical purity specific activity |
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