Assessment of the Stability of Supraphysiological Ascorbate in Human Blood: Appropriate Handling of Samples from Clinical Trials For Measurements of Pharmacological Ascorbate.

Assessment of the Stability of Supraphysiological Ascorbate in Human Blood: Appropriate Handling of Samples from Clinical Trials For Measurements of Pharmacological Ascorbate. Radiat Res. 2019 Apr 30;: Authors: Petronek MS, Wagner BA, Hollenbeck NJ, Caster JM, Spitz DR, Cullen JJ, Buettner GR, Allen BG Abstract Based on encouraging results from several early-phase clinical trials, there is renewed interest in the use of pharmacological ascorbate (i.e., intravenous administration resulting in >≈10 mM plasma ascorbate concentrations) in combination with standard-of-care cancer treatments including radiation and/or chemotherapy. Under normal, healthy physiological conditions, humans maintain plasma ascorbate concentrations in the range of 40-80 μM. However, in vivo antitumor activity requires supraphysiological plasma concentrations on the order of ≈20 mM. The stability of ascorbate in whole blood has been well studied. The goal of this work was to determine the appropriate handling methods of blood samples, after treatment with pharmacological ascorbate, which allow for the optimal measurement of ascorbate in plasma for dosing verification. Our findings indicate that ascorbate concentrations (mM) are relatively stable in whole blood collected in sodium heparin tubes and stored on ice (or at 4°C) for up to 24 h. After 24 h, ascorbate levels in plasma are relatively stable at 4°C for up to 72 h. At -20°C, plasma concentrations...
Source: Radiation Research - Category: Physics Authors: Tags: Radiat Res Source Type: research