Solid phase extraction of palbociclib from palbociclib-loaded therapeutic micelles: Novel synthesis of hybrid reduced graphene oxide-modified magnetic iron oxide (rGO@SiO2@Fe3O4)nanosorbent-based plasma extraction and pharmacokinetics study in rats.

Accurate and sensitive quantification of anticancer agents in biological matrices is challenging yet crucial for pharmacokinetic evaluation and therapeutic monitoring. In this study, a reduced graphene oxide-modified magnetic iron oxide nanosorbent (rGO@SiO2@Fe3O4) was synthesized via in-situ co-precipitation and the same was applied for the selective extraction and enrichment of palbociclib (PLB), using bosutinib (BSTB) as an internal standard. The nanosorbent was comprehensively characterized by electron microscopy with elemental mapping (FE-SEM/EDX), surface vibrational spectroscopy (ATR-FTIR), powder X-ray diffraction (PXRD), and superconducting quantum interference device (MPMS) magnetometer. The synthesized hybrid nanosorbent demonstrated favourable morphological, structural, and magnetic properties, enabling rapid magnetic separation and enhanced surface interactions. The established chromatographic analysis showed excellent linearity across 100-10,000 ng/mL, alongside a quantification limit of 100 ng/mL and a minimum detectable concentration of 50 ng/mL. Application of the developed method to rat plasma samples yielded good recovery and reproducibility, validating its performance in real biological matrices. In addition, PLB-loaded TPGS micelles (100, 125, and 150 mg) were successfully formulated, exhibiting particle sizes of 13.3-15.8 nm, supporting their potential for drug delivery applications. The integration of magnetic separability with enhanced sorption capacity makes rGO@SiO2@Fe3O4 a reusable and environmentally sustainable platform for plasma extraction. This work offers a promising strategy for sensitive, reliable, and environmental friendly quantification of PLB.