Selective extraction of theophylline from plasma by copper-doped magnetic microspheres prior to its quantification by HPLC

Abstract

The authors describe the preparation of copper-doped magnetic microspheres (Cu-FeO) by a solvothermal method. Due to their good magnetic property and high affinity for compounds containing an imidazole moiety (containing N-H), they are excellent adsorbents for such compounds as tested by eighteen compounds. Specifically, a method has been developed for magnetic solid-phase extraction (MSPE) of theophylline (TP) from plasma. The method enables selective enrichment of TP over many potential interferents that can occur in plasma. Following elution with alkaline methanol, TP was quantified by HPLC-UV at a detection wavelength of 272 nm. Under the optimized conditions, a linear response is found for the 0.02 to 20 μg·mL concentration range, and the limit of detection is as low as 3 ng·mL. Recoveries from spiked samples range from 91.2 to 100.4%, and the repeatabilities are between 2.9 and 12% (for n = 6). The method was successfully applied to the determination of TP in rabbit and rat plasma. Graphical abstract Copper-doped magnetic microspheres are described that show good magnetic property and high affinity for compounds containing an imidazole moiety (containing an N-H group). They were successfully applied to the selective extraction of theophylline in plasma.

Intermittent Hypoxia Inhibits Hepatic CYP1a2 Expression and Delays Aminophylline Metabolism

“…Quantitation of Aminophylline and Warfarin. Drug concentrations were assessed by HPLC [19,20] and DAS for CDM 2.0 software [21]. e area under the curve from 0 to t (AUC 0-36 or 144 h ) and 0 to ∞ (AUC 0-∞ ), half-life (T 1/2 ), elimination rate constant (K e ), apparent volume of distribution (V d ), clearance (CL), and peak maximum concentration (C max ) were calculated.…”

Ultra-High Adsorption Capacity of Core–Shell-Derived Magnetic Zeolite Imidazolate Framework-67 as Adsorbent for Selective Extraction of Theophylline

“…The choice of a suitable adsorbent is vital in MSPE and depends primarily on the nature of the sample being tested [ 17 ]. To date, MSPE has been reported to perform selective extraction of TP from tea and plasma samples, using molecular-imprinted polymers (MIP) [ 18 ], copper-doped magnetic microspheres [ 19 ], and metal–organic framework (MOF) [ 20 ] as magnetic adsorbents. However, these absorbents have a limited adsorption capacity.…”