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Rationale: In order to characterize the intracellular pharmacokinetic properties of tigecycline, we developed and fully validated a liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for quantification of tigecycline in human lung epithelial (BEAS‐2B) cells and polymorphonuclear neutrophils (PMNs). Methods: Tetracycline was used as an internal standard and chromatographic separation was achieved on a C18 Hypersil Gold aQ column using two mobile phases, a solution of water (containing 0.1% formic acid) and acetonitrile. The flow rate was 0.4 mL/min for 5.0 min. Tigecycline drug uptake was evaluated by incubating the BEAS‐2B cells and the PMNs for up to 3 h at tigecycline concentrations of 1 mg/L. Results: The assay was linear over the tested concentration range of 0.01–2 mg/L for tigecycline in BEAS‐2B cells and PMNs (r2 >0.99). The inter‐ and inter‐day precisions (RSD, %) were <10.02% and the accuracies (%) were within the range of 85–115%. The uptake study showed that after incubation with tigecycline (1 mg/L) for 3 h at 37°C, the intracellular peak concentration of BEAS‐2B cells was 14.44 ± 7.12 mg/L at 1 h, and 41.43 ± 25.66 mg/L in PMNs at 20 min. The mean intracellular concentrations fluctuated in the range of 0.8–14.44 mg/L in BEAS‐2B cells and 10.14–41.43 mg/L in PMNs for 1 mg/L tigecycline exposure. Conclusions: Validated LC/MS/MS is a simple, rapid, and sensitive method for determining the intracellular concentration of tigecycline, and tigecycline has good penetrations both in human BEAS‐2B cells and PMNs. The method can be efficiently used for future studies of the intracellular pharmacokinetics of tigecycline. [ABSTRACT FROM AUTHOR]

Voriconazole is used to prevent invasive pulmonary aspergillosis. However, little is known about the concentrations of voriconazole in human lung epithelial cells (A549), which is the target for preventing invasive pulmonary aspergillosis. The goal of this study was to develop a high-performance liquid chromatography–tandem mass spectrometry method to quantify voriconazole in A549 cells. A triple-quadrupole mass spectrometer in selected reaction monitoring mode was used with positive electrospray ionization. The total duration of each run was 5 min. The calibration curves fit a least squares model for the voriconazole concentration ranging from 0.625 to 160 ng/mL. Intraday and interday coefficients of variation were less than 10%. Recoveries at the concentrations of the quality control samples where greater than 85%, and the matrix effects showed that the ratios of the peak response exhibited a 15% suppression of the signal in the matrix compared to water. Voriconazole may penetrate A549 cells. However, the voriconazole uptake was slow in A549 cells, reaching a plateau at 2 h, where the dose-dependent intracellular voriconazole concentrations were 1.98 ± 0.38, 4.43 ± 0.54, and 8.14 ± 0.52 ng/mg protein for extracellular voriconazole concentrations of 5, 10, and 20 µg/mL, respectively. The uptake of voriconazole by A549 cells was linear at extracellular concentrations from 0 to 20 µg/mL. This study established a rapid and sensitive method suitable for determining voriconazole in A549 cells and described the kinetic properties of the absorption of voriconazole by A549 cells. [ABSTRACT FROM PUBLISHER]