Simultaneous determination of icotinib, osimertinib, aumolertinib, and anlotinib in human plasma for therapeutic drug monitoring by UPLC-MS/MS.

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) such as icotinib, osimertinib, and aumolertinib have emerged as promising treatment options for EGFR mutated Non-small cell lung cancer (NSCLC) patients. Additionally, anlotinib, an anti-angiogenic agent targeting VEGFR, FGFR, and PDGFR, has been used in combination with EGFR-TKIs in NSCLC cases. A method utilizing ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed and validated for quantifying icotinib, osimertinib, aumolertinib and anlotinib simultaneously in clinical TDM. The chromatographic separation was performed using a Kinetex C18 column (100 mm × 2.1 mm) and an elution gradient of ammonium acetate in water acidified with 0.1 % formic acid and in acetonitrile. The assay was validated over a linear range of 4-2000 ng/mL for icotinib, 2-1000 ng/mL for osimertinib, 1-500 ng/mL for aumolertinib, and 0.8-400 ng/mL for anlotinib, following the guidelines on bioanalytical methods by FDA. The quantification method exhibited satisfactory performance in terms of selectivity, accuracy (from 91.3 % to 107 %), precision (intra- and inter-day coeffficients of variation ranged from 0.944 % to 7.48 %), linearity, recovery (from 86.0 % to 91.9 %), matrix effect (IS-normalized matrix factors were from 96.7 % to 102 %), and stability. Overall, the method proved to be sensitive, reliable, and straightforward, enabling successful simultaneous determination of blood concentrations of icotinib, osimertinib, aumolertinib, and anlotinib in patients. The validity of the method has been confirmed across various instruments.

Development and Validation a UPLC-MS/MS Method for Quantification of Pentoxifylline in Beagle Plasma: Application for Pharmacokinetic Study of Food Effect.

Purpose: To develop an UPLC-MS/MS method for the quantitative analysis of pentoxifylline in beagle dog plasma and apply it to a pharmacokinetic study of food effect. Methods: Sample separation was achieved using a Kinetex Phenyl-Hexyl column (50 × 2.1 mm, 1.7 µm) with a gradient elution program in 5.5 min after a simple protein precipitation with methanol. Using the mobile phase that made up by 0.2% formic acid and 5mM ammonium formate water (A) and methanol (B). Quantitation was carried out using the positive ionization mode with multiple reaction monitoring (MRM). A randomized, single-dose, two-period crossover study was conducted in six fasted or fed beagles that received 400 mg pentoxifylline sustained-release tablets (Brand name: Shuanling™, CSPC Pharmaceutical Group). WinNonlin® software was used to calculate pharmacokinetic parameters. Results: The linear calibration range was 2-1000 ng/mL (r2> 0.99). Both intra- and inter-batch precision were less than 6.27%, and the accuracy ranged from 88.65% to 97.18%. Pentoxifylline was readily absorbed in fasted and fed dogs administered a dose of 400 mg (tmax:1.54h vs 1.83h). Compared to the fasted group, the AUC0→t and Cmax in the fed group increased by 1.71-fold and 1.30-fold, respectively. In the fasted group, the AUC0→t and Cmax values were 4684.08 h•ng/mL and 2402.33 ng/mL, respectively. In the fed group, these values were 8027.75 h•ng/mL and 3119.67 ng/mL. The difference in AUC0-t between the fed and fasted group was statistically significant. Conclusion: The novel optimized UPLC-MS/MS assay is an effective tool for the determination of pentoxifylline and has been successfully applied in pharmacokinetic studies of pentoxifylline in beagle dogs. The administration of pentoxifylline sustained-release tablets with food significantly increased the area under the time curve, and it is recommended that they should be administered during or shortly after feeding.