Liquid Chromatography-Tandem Mass Spectrometry Assay Suitable For Quantifying Omega-3 Epoxy-Fatty Acid Analogs In Mouse Brain And Plasma

Metabolites of omega-3 fatty acids can inhibit primary tumor growth, angiogenesis, and tumor metastasis. Effective treatment for brain tumors is an unmet need as many chemotherapies are unable to cross the blood-brain barrier efficiently. As fatty acids are capable of entering the brain, these agents may have potential for treating brain tumors. In this communication a reliable and sensitive LC-MS/MS method was developed and validated for quantitation of ethyl 16-{[(4-methylphenyl)carbamoyl]amino}hexadecanoate (CUT-EE), a urea-based analog of eicosapentaenoic acid. The assay has acceptable intra- and inter-assay accuracy and precision over the range 0.25-125ng/mL, and a lower limit of quantitation of 0.25ng/mL. Non-aqueous, mouse brain, and plasma solutions of CUT-EE were stable during short-term and long-term storage, and after three freeze-thaw cycles. This method was applied to determine concentrations of CUT-EE in brain and plasma following administration to mice at 50mg/kg. CUT-EE was cleared from the plasma within 24hr, whilst concentrations in the brain increased over 24hr and remained stable out to 48hr. The calculated area under the concentration curve in brain was over 100 times greater than that found in plasma, supporting further investigations of CUT-EE for its potential in treating brain cancers.