Restricted access magnetic core-mesoporous shell microspheres with C8-modified interior pore walls for the identification of 20( S )-protopanaxadiol metabolites in rat plasma using UPLC-Q-TOF-MS/MS

Nanomaterial-based magnetic solid-phase extraction in pharmaceutical and biomedical analysis

Magnetic solid-phase extraction (MSPE) holds significant scientific and technological interest as a novel sample preparation method for complex samples due to its easy operation, swift separation, high adsorption efficiency, and environmental friendliness. As the core of MSPE, magnetic sorbents have captured tremendous attention in recent years. Various promising nanomaterials, such as metal-organic frameworks and covalent organic frameworks, have been synthesized and utilized as sorbents in pharmaceutical and biomedical analysis. This review intends to (1) summarize recent progress of magnetic sorbents applied in this area and discuss their advantages, disadvantages, possible interaction mechanisms with the target substances; (2) explore their innovative applications in the analysis of pharmaceuticals, proteins, peptides, nucleic acids, nucleosides, metabolites, and other disease biomarkers from 2021 to 2024; (3) present the integration of MSPE with emerging analytical technologies; and (4) discuss the current challenges and future perspectives. It is expected to provide references and insights for the development of novel magnetic sorbents and their applications in bioanalysis.

Preparation of restricted access monolithic tip via unidirectional freezing and atom transfer radical polymerization for directly extracting magnolol and honokiol from rat plasma followed by liquid chromatography analysis

In the present study, a novel strategy based on unidirectional freezing and atom transfer radical polymerization combined with activator regenerated by electron transfer (ARGET-ATRP) was applied to synthesizing orderly macroporous monolithic column with restricted-access (RA) property in a 1000μL pipette tip. The RA column was composed of hydrophobic inner column (poly(styrene-co-ethylene glycol dimethacrylate) and hydrophilic outer layer (poly-hydroxyethyl methacrylate chain) which was grafted on the hydrophobic surface by means of the second ARGET-ATRP reaction. The as-prepared RA monolithic tip was connected to a 2mL syringe for directly extracting magnolol and honokiol from rat plasma just by manually pushing operation. The surface morphology and chemical composition of the column were characterized by scanning electronic microscope, infrared spectroscopy and X-ray photoelectron spectroscopy respectively. The determined results of evaluation experiments based on the optimized solid phase extraction conditions showed that the RA column possessed good protein exclusion power, extraction recovery and reusability. The constructed RA-SPE-HPLC/UV method for simultaneously analyzing magnolol and honokiol in rat plasma was validated with quality control (QC) samples at four concentration levels. Good precision (RSDs, 3.39~11.16%) and acceptable accuracy (relative recoveries, 89.52%~108.42%) were obtained for intra- and inter-day assays. The determined results of real rat plasma as well as the standard-addition samples demonstrated the developed method with good accuracy and precision. It can be extrapolated from the experimental results that this simple and cost-efficient RA-SPE method is also suitable for directly extracting other hydrophobic constituents in biological body fluid for therapeutic drug monitoring or pharmacokinetic study.