Bioanalysis of monodisperse HO-PEG-OH polymers in MCF-7 cells by UHPLC-MS/MS coupled with μ-SPE to improve greenness and sensitivity.

Monodisperse polyethylene glycol (PEG) derivatives offer significant advantages over conventional polydisperse PEGs for biomedical applications due to their precisely defined molecular structures. This study establishes an eco-efficient, selective, and sensitive analytical assay integrating microscale solid-phase extraction (μ-SPE) with ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) to investigate the cellular uptake of HO-PEG-OH polymers in MCF-7 cells. The method achieved greater than 91% recovery from 20 μL lysates using M-PEG-OH as the internal standard, with validated linearity (10-1000 ng/mL, R > 0.997), accuracy (relative error <  ± 7.49%), and precision (RSD < 7.50%). The novelty of the assay is the harmonization of analytical performance with green analytical chemistry principles. The validated method provides a robust platform for studying monodisperse PEG derivatives while addressing growing demands for sustainable analytical technologies. Green analytical chemistry metric assessments confirmed the environmental sustainability of the method. Cellular pharmacokinetic analysis revealed time-/concentration-dependent uptake kinetics of HO-PEG-OH polymers in MCF-7 cells, showing 3.2-fold accumulation between 0.5 and 48 h exposure. These findings offer important insights for PEG-based drug delivery system optimization and establish a new standard for environmentally conscious bioanalytical method development.