Here, a QuEChERS (quick, easy, cheap, effective, rugged, and safe) pretreatment method was combined with UPLC-MS/MS to facilitate the rapid and reliable simultaneous detection of five calcium channel blockers (CCBs) in human plasma. For this approach, samples were treated with 1 mL of acetonitrile, 350 mg of magnesium sulfate, and 70 mg of PSA adsorbent prior to centrifugation. Supernatants then underwent gradient elution for 8 min with an Agilent C18 column using an acetonitrile-water solution supplemented with 5 mmol⋅L−1 of ammonium acetate. This technique exhibited a good linear response in the 1–800 ng⋅mL−1 range for the analyzed drugs, with an R2≥ 0.9921, an accuracy of 87.54–113.05%, a matrix effect (ME) of 91.21–116.39%, a precision of 0.19–11.64%, and stability of no more than 10.05%. This time-saving QuEChERS reagent-based pretreatment technique thus allowed for the simultaneous and accurate detection of five CCBs in human plasma samples, providing a promising new basis for therapeutic drug monitoring in patients with hypertension.

A reliable and rapid method employing QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) pretreatment coupled with ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) was successfully developed and validated for the analysis of nine tyrosine kinase inhibitors (TKIs) in human plasma. Biological samples were extracted with acetonitrile and salted out with 350 mg of anhydrous magnesium sulfate (MgSO4), followed by purification with 40 mg of ethyl enediamine-N-propylsilane (PSA) adsorbents. All analytes and internal standards (IS) were separated on the Hypersil GOLD VANQUISH C18 (2.1 mm × 100 mm, 1.9 μM) column using the mobile phases composed of acetonitrile (phase A) and 0.1% formic acid in water (phase B) for 8.0 min. Detection was performed by selection reaction monitoring (SRM) in the positive ion electrospray mode. Lenvatinib, sorafenib, cabozantinib, apatinib, gefitinib, regorafenib, and anlotinib rendered good linearity over the range of 0.1–10 ng/ml, and 1–100 ng/ml for tivantinib and galunisertib. All linear correlation coefficients for all standard curves were ≥ 0.9966. The limits of detection (LOD) and the limits of quantitation (LOQ) ranged from 0.003 to 0.11 ng/ml and 0.01–0.37 ng/ml, respectively. The method was deemed satisfactory with an accuracy of -7.34–6.64%, selectivity, matrix effect (ME) of 90.48–107.77%, recovery, and stability. The proposed method is simple, efficient, reliable, and applicable for the detection of TKIs in human plasma samples as well as for providing a reference for the clinical adjustment of drug administration regimen by monitoring the drug concentrations in the plasma of patients.

Series of FePt/Fe multilayers with different layer thicknesses have been deposited on Si substrates by magnetron sputtering and post annealing at different temperatures and durations. The structure, surface morphology, composition, and magnetic properties of the deposited films have been characterized by XRD, SEM, EDX and VSM. It is found that after annealing at temperatures above 500°C, FePt phase undergoes a phase transition from disorder fcc into ordered fct structure, and become a hard magnetic phase. For [FePt/Fe]n multilayer with varying Fe layer thickness, lattice constants and grain sizes change with Fe layer thickness and annealing temperature. The coercivities of [FePt/Fe]n multilayers decrease with Fe layer deposition time, and the energy product (BH)max shows a maximum with Fe layer thickness. Optimization on layer thickness leads a high (BxH)max value of 15.2MGOe for [FePt(8min)/Fe(4min)]8. The effects of quick annealing and Ag underlayer on the structure and magnetic properties were also studied.