Effect of liposome composition on β-blocker interactions studied by capillary electrokinetic chromatography

Liposome capillary electrokinetic chromatography was used to investigate the interactions between three β-blockers of different hydrophobicity and various liposome solutions. The studied β-blockers comprised alprenolol, propranolol, and carvedilol. The composition of the liposome solutions, containing 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine, 1,2-dioleoyl-sn-glycero-3-phos-phoethanolamine, 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-l-serine, and cholesterol in various molar ratios, was designed by a response surface methodology-central composite design approach. Subsequently, after conducting the liposome capillary electrokinetic chromatography experiments and determining the retention factors from the electrophoretic mobilities of the compounds, and further calculating the distribution coefficients, an analysis of variance was performed. After extracting the statistical models, optimal operational conditions were obtained based on the developed models. To further investigate the interactions between the β-blockers and the liposomes, nanoplasmonic sensing experiments were carried out on two different liposome systems. The overall results demonstrate the strong influence of cholesterol and 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-l-serine on the distribution coefficients.

Evaluation of the enantioselectivity of capillary electrokinetic chromatography using ethanediamine-bonded poly (glycidyl methacrylate) microspheres as the pseudostationary phases

In this work, a new capillary electrokinetic chromatography (EKC) approach using ethanediamine-bonded poly (glycidyl methacrylate) (Ami-PGMA) microspheres as pseudostationary phases (PSPs) for enantioseparation with a polysaccharide, chondroitin sulfate E (CSE), as the chiral selector. The CSE@Ami-PGMA EKC system was applied to enantioseparate basic drugs, and distinct improved separations of tested enantiomers were obtained while comparing with the single CSE system (the resolution increased from 0.41 to 1.26 for nefopam, from 1.24 to 2.15 for laudanosine, and from 0.92 to 2.36 for amlodipine). The Ami-PGMA microspheres were fully characterized by scanning electron microscopy (SEM) and Fourier Transform Infrared (FT-IR) spectroscopy, and the results showed Ami-PGMA microspheres were uniform and spherical in size (1 μm). Several principal parameters were systematically investigated, and the optimal chiral separations were obtained with Tris/H₃ PO₄ (20 mM, pH 2.4, and 3.4 for NEF) containing 2.5% (w/v) CSE and 20-μg Ami-PGMA microspheres in 20°C. Subsequently, the concentrations of Ami-PGMA microspheres and CSE were proved to be the dominant factors for the separation in the CSE@Ami-PGMA EKC system by Statistical Product and Service Solutions (SPSS).