With insulin methanol water, and the ion pairing agent, hydrochloric acid and trifluroacetic acid (TFA), the character of the first plateau (FP) on the elution curve of frontal analysis in reversed phase liquid chro...With insulin methanol water, and the ion pairing agent, hydrochloric acid and trifluroacetic acid (TFA), the character of the first plateau (FP) on the elution curve of frontal analysis in reversed phase liquid chromatography (RPLC) was investigated by on line UV spectrometry and identified with nuclear magnetic resonance (NMR) spectrometry and mass spectrometry. The profile of the FP is the same as that of a usual elution curve of methanol in frontal analysis (FA). When the insulin concentration was limited to a certain range, the height of the FP was found to be proportional to the insulin concentration in mobile phase and its length companying to shorten. The FP profile on the intersection of two tangents reflects the components of the microstructure in the depth direction of the bonded stationary phase layer and the desorption dynamics of the displaced components. The displaced methanol was quantitatively determined by NMR and on line UV spectrometries. TFA with high UV absorbance can not be used as an ion pairing agent for the investigation of the FP in RPLC, but it can be used as a good marker to investigate the complicated transfer process of components in the stationary phase in RPLC. A stoichiometric displacement process between solute and solvent was proved to be valid in both usual and FA in RPLC. From the point of view of dynamics of mass transfer, the solutes can only contact to the surface of stationary phase in usual RPLC, while solute can penetrate into it in FA of RPLC. The solvation of insulin in methanol and water solution as an example indicating the usage of the FP in the FA was also investigated in this paper.展开更多
A rapid, sensitive, and robust reversed-phase liquid chromatography with tandem mass spectrometry method was developed and validated for the determination of total and unbound ceritinib, a secondgeneration ALK inhibit...A rapid, sensitive, and robust reversed-phase liquid chromatography with tandem mass spectrometry method was developed and validated for the determination of total and unbound ceritinib, a secondgeneration ALK inhibitor, in patient plasma and brain tumor tissue samples. Sample preparation involved simple protein precipitation with acetonitrile. Chromatographic separation was achieved on a Waters ACQUITY UPLC BEH C_(18) column using a 4-min gradient elution consisting of mobile phase A(0.1% formic acid in water) and mobile phase B(0.1% formic acid in acetonitrile), at a flow rate of 0.4 m L/min. Ceritinib and the internal standard([^(13)C_6]ceritinib) were monitored using multiple reaction monitoring mode under positive electrospray ionization. The lower limit of quantitation(LLOQ) was 1 n M of ceritinib in plasma. The calibration curve was linear over ceritinib concentration range of 1–2000 n M in plasma. The intra-and interday precision and accuracy were within the generally accepted criteria for bioanalytical method( o15%).The method was successfully applied to assess ceritinib brain tumor penetration, as assessed by the unbound drug brain concentration to unbound drug plasma concentration ratio, in patients with brain tumors.展开更多
文摘With insulin methanol water, and the ion pairing agent, hydrochloric acid and trifluroacetic acid (TFA), the character of the first plateau (FP) on the elution curve of frontal analysis in reversed phase liquid chromatography (RPLC) was investigated by on line UV spectrometry and identified with nuclear magnetic resonance (NMR) spectrometry and mass spectrometry. The profile of the FP is the same as that of a usual elution curve of methanol in frontal analysis (FA). When the insulin concentration was limited to a certain range, the height of the FP was found to be proportional to the insulin concentration in mobile phase and its length companying to shorten. The FP profile on the intersection of two tangents reflects the components of the microstructure in the depth direction of the bonded stationary phase layer and the desorption dynamics of the displaced components. The displaced methanol was quantitatively determined by NMR and on line UV spectrometries. TFA with high UV absorbance can not be used as an ion pairing agent for the investigation of the FP in RPLC, but it can be used as a good marker to investigate the complicated transfer process of components in the stationary phase in RPLC. A stoichiometric displacement process between solute and solvent was proved to be valid in both usual and FA in RPLC. From the point of view of dynamics of mass transfer, the solutes can only contact to the surface of stationary phase in usual RPLC, while solute can penetrate into it in FA of RPLC. The solvation of insulin in methanol and water solution as an example indicating the usage of the FP in the FA was also investigated in this paper.
基金supported by the United States Public Health Service Cancer Center Support Grant P30 CA022453Novartis for providing the study drug and isotope-labeled internal standard and providing financial support for the clinical study
文摘A rapid, sensitive, and robust reversed-phase liquid chromatography with tandem mass spectrometry method was developed and validated for the determination of total and unbound ceritinib, a secondgeneration ALK inhibitor, in patient plasma and brain tumor tissue samples. Sample preparation involved simple protein precipitation with acetonitrile. Chromatographic separation was achieved on a Waters ACQUITY UPLC BEH C_(18) column using a 4-min gradient elution consisting of mobile phase A(0.1% formic acid in water) and mobile phase B(0.1% formic acid in acetonitrile), at a flow rate of 0.4 m L/min. Ceritinib and the internal standard([^(13)C_6]ceritinib) were monitored using multiple reaction monitoring mode under positive electrospray ionization. The lower limit of quantitation(LLOQ) was 1 n M of ceritinib in plasma. The calibration curve was linear over ceritinib concentration range of 1–2000 n M in plasma. The intra-and interday precision and accuracy were within the generally accepted criteria for bioanalytical method( o15%).The method was successfully applied to assess ceritinib brain tumor penetration, as assessed by the unbound drug brain concentration to unbound drug plasma concentration ratio, in patients with brain tumors.
