Elimination of ascorbic acid after high-dose infusion in prostate cancer patients: a pharmacokinetic evaluation.
Level 4 - case-series / case-control
Single-arm uncontrolled pharmacokinetic study
PubMed 25220574 · doi:10.1111/bcpt.12323
What was done
Ten patients with metastatic prostate cancer received fixed intravenous ascorbic acid infusions at doses of 5, 30, and 60 g over a 4-week period. Serial plasma ascorbic acid levels were measured consecutively to evaluate pharmacokinetic parameters across the dosing range.
What was found
Ascorbic acid displayed first-order elimination kinetics throughout the dosing range. A 60 g IV dose produced a peak plasma concentration of 20.3 mM. The mean elimination half-life was 1.87 ± 0.40 hr, volume of distribution was 0.19 ± 0.05 L/kg, and clearance was 6.02 L/hr (100 mL/min). No differences in pharmacokinetic parameters were observed between weeks or doses.
Why it matters
This study provides human pharmacokinetic benchmarks for high-dose intravenous ascorbic acid, demonstrating that its rapid clearance prevents post-infusion maintenance of potentially cytotoxic concentrations without continuous maintenance dosing.
Limits
The study is limited by a very small sample size (n = 10) and an uncontrolled design. The population was restricted to patients with metastatic prostate cancer and normal kidney function. Clinical efficacy, tumor response, and adverse clinical outcomes were not reported in the abstract.
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