Ultra-performance hydrophilic interaction liquid chromatography/tandem mass spectrometry for the determination of everolimus in mouse plasma.

Ultra-performance hydrophilic interaction liquid chromatography (UPHILIC) interfaced with the electrospray ionization (ESI) source of a tandem mass spectrometer (MS/MS) was developed for the simultaneous determination of everolimus in mouse plasma samples. UPHILIC was performed on a sub-2 microm bare silica particle packing with the column pressure under traditional high-performance liquid chromatography (HPLC) to allow fast separation of pharmaceutical compounds within a chromatographic analysis time of 1 min. This UPHILIC technology is comparable with reversed-phase ultra-performance liquid chromatography (RPUPLC) in terms of chromatographic efficiency but demands neither expensive ultra-high-pressure instrumentation nor new laboratory protocols. With the ESI source, multiple reaction monitoring (MRM) of the ammoniated adduct ions of the analyte was used for tandem mass spectrometric detection. The retention mechanism profiles of the test compounds under HILIC conditions were explored. The influences of experimental factors such as the compositions of mobile phases on the chromatographic performance and the ionization efficiency of the test compounds in positive ion mode were investigated. A UPHILIC/MS/MS approach following a protein precipitation procedure was applied for the quantitative determination of everolimus at the low ng/mL region in support of a pharmacodynamic study. The analytical results obtained by the UPHILIC/MS/MS approach were fond to be in good agreement with those obtained by the RPUPLC/MS/MS method in terms of assay sample throughput, sensitivity and accuracy.

Hydrophilic interaction liquid chromatography/tandem mass spectrometry for the simultaneous determination of dasatinib, imatinib and nilotinib in mouse plasma.

Hydrophilic interaction liquid chromatography (HILIC) interfaced with atmospheric pressure ionization (API) sources and a tandem mass spectrometer (MS/MS) was developed for the simultaneous determination of dasatinib, imatinib and nilotinib in mouse plasma samples. The retention profiles of all analytes on several silica stationary phases under HILIC conditions were explored. The influences of experimental factors such as the compositions of mobile phases on the chromatographic performance and the ionization efficiency of all analytes in positive ion mode were investigated. The applicability of the proposed HILIC/MS/MS approach following a protein precipitation procedure for the quantitative determination of dasatinib, imatinib and nilotinib at low nano-mole levels was examined with respect to assay specificity and linearity. The analytical results obtained by various HILIC/MS/MS approaches were found to be in good agreement with those obtained by reversed-phase liquid chromatography/tandem mass spectrometry (RPLC/MS/MS) methods in terms of assay sample throughputs, sensitivity and accuracy. Furthermore, the potential of matrix ionization suppression on the proposed HILIC/MS/MS systems was investigated using the post-column infusion technique.

Ultra-performance hydrophilic interaction LC-MS/MS for the determination of metformin in mouse plasma.

INTRODUCTION: Ultra-performance (UP) hydrophilic interaction LC (UPHILIC) interfaced with an ESI source and MS/MS was developed for the determination of metformin in mouse plasma samples. MATERIALS & METHODS: Several silica stationary phases under HILIC conditions were adapted to evaluate the retention mechanism profiles of the analyte. The influences of experimental factors such as the compositions of mobile phases on the chromatographic performance and the ionization efficiency of the test compounds in positive ion mode were investigated. The applicability of the proposed UPHILIC-MS/MS approach following a protein precipitation procedure for the quantitative determination of metformin at nanomole levels was examined with respect to assay specificity and linearity. RESULTS: The analytical results obtained by the described UPHILIC-MS/MS approach were found to be in good agreement with those obtained by an ion-pair UPLC-MS/MS method in terms of assay sample throughput, sensitivity and accuracy. CONCLUSION: The results suggested that it is feasible to convert a reversed-phase UPLC-MS/MS method to a UPHILIC-MS/MS method by simply switching the analytical columns while maintaining the rest of the experimental conditions for polar pharmaceutical analyses with enhanced retention and sensitivity.