Sensitive analysis of tyrosine kinase inhibitors in plasma using polypropylene fabric-solid phase extraction combined with liquid chromatography-tandem mass spectrometry

Accurate quantification of tyrosine kinase inhibitors (TKIs) in plasma is essential for therapeutic drug monitoring (TDM). This study presents a novel solid phase extraction (SPE) method employing hydrophobic polypropylene fabric (PPF)—a fibrous material derived from oil-absorbent pads—as the sorbent. The PPF-SPE device was prepared by directly packing fluffed PPF into syringe barrels, eliminating the need for sieve plates and simplifying column assembly. Integrated with liquid chromatography-tandem mass spectrometry (LC-MS/MS), the method enabled sensitive determination of eight clinically relevant TKIs (afatinib, alectinib, ceritinib, dasatinib, sunitinib, pazopanib, tamoxifen, and ibrutinib) in plasma. Key parameters, including PPF amount, sample pH, and desorption conditions, were systematically optimized, yielding high extraction recoveries (83.1–96.4 %) and good reproducibility (RSDs<5.5 %). The method showed excellent linearity (R²>0.99), low detection limits (0.017–0.055 ng/mL), and high intra-/inter-day recoveries (85.1 %–102.6 %) and precision (RSDs<5.3 %). Its practical applicability was validated in spiked plasma under a single-blind design, yielding relative errors of –8.2 % to 5.4 %. Compared to traditional SPE methods, PPF-SPE offers significant advantages in operational simplicity, cost-effectiveness, high throughput, and environmental sustainability.