BACKGROUND: Low-dose methotrexate is used for the treatment of rheumatoid arthritis and juvenile idiopathic arthritis, but its effectiveness greatly varies between individuals. Therapeutic drug monitoring of intracellular methotrexate metabolites, the γ-polyglutamates (MTXGlu(n)), in human erythrocytes has shown promise in providing a basis for individualization of therapy. RESULTS: This work presents expedient methodology for the analysis of MTXGlu(1-7) in human erythrocytes by ion-pair UPLC with detection by tandem MS (UPLC-ESI-MS/MS). The use of N,N-dimethylheptylamine as an ion-pair agent was found to be favorable over others. Thermal extraction of erythrocyte lysates provides a simple one-step extraction procedure. The entire chromatographic run time is 6 min and the assay was validated within the therapeutic range of these metabolites CONCLUSION: The developed sample preparation procedure in combination with ion-pair UPLC-ESI-MS/MS analysis allowed for expedient quantitation of MTXGlu(1-7) in human erythrocytes. The rapid analysis time would enable therapeutic drug monitoring of MTXGlu(1-7) in the clinic.
BACKGROUND: Low-dose methotrexate is used for the treatment of rheumatoid arthritis and juvenile idiopathic arthritis, but its effectiveness greatly varies between individuals. Therapeutic drug monitoring of intracellular methotrexate metabolites, the γ-polyglutamates (MTXGlu(n)), in human erythrocytes has shown promise in providing a basis for individualization of therapy. RESULTS: This work presents expedient methodology for the analysis of MTXGlu(1-7) in human erythrocytes by ion-pair UPLC with detection by tandem MS (UPLC-ESI-MS/MS). The use of N,N-dimethylheptylamine as an ion-pair agent was found to be favorable over others. Thermal extraction of erythrocyte lysates provides a simple one-step extraction procedure. The entire chromatographic run time is 6 min and the assay was validated within the therapeutic range of these metabolites CONCLUSION: The developed sample preparation procedure in combination with ion-pair UPLC-ESI-MS/MS analysis allowed for expedient quantitation of MTXGlu(1-7) in human erythrocytes. The rapid analysis time would enable therapeutic drug monitoring of MTXGlu(1-7) in the clinic.
Authors: Rakesh K Singh; Leon van Haandel; Paul Kiptoo; Mara L Becker; Teruna J Siahaan; Ryan S Funk Journal: Eur J Pharmacol Date: 2019-04-02 Impact factor: 4.432
Authors: Dala N Daraghmeh; Mahin Moghaddami; Larisa Bobrovskaya; Susanna M Proudman; Michael D Wiese Journal: Anal Bioanal Chem Date: 2022-07-07 Impact factor: 4.478
Authors: Ryan Morrow; Ryan Funk; Mara Becker; Ashley Sherman; Leon Van Haandel; Taina Hudson; Rebecca Casini; Valentina Shakhnovich Journal: Pharmaceuticals (Basel) Date: 2021-05-14