JP4-039 radio-protects prior to, and radio-mitigates after ionizing radiation by neutralizing reactive oxygen species. We developed and validated an LC-MS/MS assay for the quantitation of JP4-039 in murine plasma. Methanol protein precipitation of 50μL plasma was followed by isocratic reverse phase chromatography for a 6min run time, and electrospray positive mode ionization mass spectrometric detection. The plasma assay was linear from 1 to 1000ng/mL with appropriate accuracy (97.1-107.6%) and precision (3.7-12.5%CV), and fulfilled FDA guidance criteria. Recovery was 77.2-136.1% with moderate ionization enhancement (10.9-39.5%). Plasma freeze-thaw stability (98.8-104.2%), stability for 13.5 months at -80°C (93.1-105.6%), and stability for 4h at room temperature (94.2-97.6%) were all acceptable. Limited cross-validation to tissue homogenates suggested that these could also be analyzed for JP4-039 accurately. This assay has been directly applied to determine the pharmacokinetics of JP4-039 in C57BL/6 male mice after IV administration of 20mg/kg JP4-039 and will be extended to other studies of this agent.
Keywords: Assay; Hydroxylamine species; JP4-039; Mice; Nitroxide; Oxoammonium cation; Pharmacokinetics; Radiation mitigation; Radiation protection; Tandem mass spectrometry; Validation.
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