In this work, enantioseparation of four chiral fluoroquinolones (FQs), namely, ofloxacin, gemifloxacin, lomefloxacin, and gatifloxacin, was achieved by capillary electrophoresis with sulfated-β-cyclodextrin (S-β-CD) as chiral selector. Factors affecting the enantiomeric resolution, such as the concentrations of S-β-CD, BGE pH conditions, and the buffer types and concentrations, were optimized and discussed. A BGE consisting of 30 g/L S-β-CD and 30-mM phosphate at pH 4.0 was found fit for enantiomeric resolution of ofloxacin and gemifloxacin, while the same BGE at pH 3.0 was suitable for enantioseparation of lomefloxacin and gatifloxacin. The pH-dependent experiments showed that separation resolutions of four FQs enantiomers were significantly affected by BGE pH, which was thought to be related with the varying electrostatic attraction between the enantiomers and chiral selector. To verify this speculation, molecular docking studies were used for further investigation of the enantiomeric recognition mechanism of S-β-CD. Molecular model indicated that hydrophobic effect and hydrogen bond were involved in host-guest inclusion, but the electrostatic attraction enhanced the chiral discrimination by increasing the difference in binding energy between individual enantiomers and S-β-CD. This work provided a further insight into the chiral recognition mechanisms of CD derivatives.

中文翻译：

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以硫酸化-β-环糊精为手性选择剂的毛细管电泳分离四种手性氟喹诺酮类药物的实验和计算研究

在这项工作中，以硫酸化-β-环糊精 (S-β-CD) 作为手性选择剂，通过毛细管电泳实现了四种手性氟喹诺酮类 (FQ) 的对映体分离，即氧氟沙星、吉米沙星、洛美沙星和加替沙星。优化和讨论了影响对映体分辨率的因素，例如 S-β-CD 的浓度、BGE pH 条件以及缓冲液类型和浓度。发现由 30 g/L S-β-CD 和 30-mM 磷酸盐组成的 BGE 在 pH 4.0 下适用于氧氟沙星和吉米沙星的对映体拆分，而在 pH 3.0 下的相同 BGE 则适用于洛美沙星和加替沙星的对映体分离。pH 依赖性实验表明，四种 FQ 对映体的分离分辨率受 BGE pH 显着影响，这被认为与对映异构体和手性选择器之间不同的静电吸引力有关。为了验证这一推测，分子对接研究被用于进一步研究 S-β-CD 的对映体识别机制。分子模型表明疏水作用和氢键参与了主客体包含，但静电引力通过增加个体对映体和 S-β-CD 之间结合能的差异来增强手性区分。这项工作进一步深入了解 CD 衍生物的手性识别机制。分子模型表明疏水作用和氢键参与了主客体包含，但静电引力通过增加个体对映体和 S-β-CD 之间结合能的差异来增强手性区分。这项工作进一步深入了解 CD 衍生物的手性识别机制。分子模型表明疏水作用和氢键参与了主客体包含，但静电引力通过增加个体对映体和 S-β-CD 之间结合能的差异来增强手性区分。这项工作进一步深入了解 CD 衍生物的手性识别机制。