衍生化β-环糊精手性固定相高效液相色谱法拆分米那普仑对映体及其分离机制

建立了新型抗抑郁药米那普仑在环糊精手性固定相上的高效液相色谱拆分方法。在反相色谱条件下采用未衍生化β-环糊精(Cyclobond I 2000)、乙酰基-β-环糊精(AC-β-CD)、2,3-二甲基-β-环糊精(DM-β-CD)、3,5-二甲基苯基氨基甲酸酯-β-环糊精(DMP-β-CD)4种手性柱分离米那普仑对映体。考察了固定相、流动相比例、pH、流速和柱温对拆分的影响。利用分子对接和结合能计算方法,研究米那普仑分子与AC-β-CD的对接过程,探讨其可能的分离机制。优化后的拆分条件如下:固定相为乙酰基-β-环糊精手性柱Astec CYCLOBONDTMI 2000 AC(25 cm×4.6 mm,5μm),流动相为乙腈-0.1%(体积分数)pH 5.0醋酸三乙胺溶液(TEAA)(5∶95,v/v),流速为0.4mL/min,柱温为25℃,检测波长为220 nm。在此条件下,米那普仑对映体获得快速拆分,分离度(Rs)为1.74,理论塔板数为10 125。分子模拟结果表明引起手性识别的作用力主要是环糊精衍生化的乙酰基导致的氢键作用差异。该方法快速、高效、重现性好。

Enantioseparation of milnacipran enantiomers and the separation mechanism on β-cyclodextrin-based chiral stationary phases by high performance liquid chromatography

A high performance liquid chromatography method was established for the enantiomeric separation of milnacipran enantiomers on β-cyclodextrin-based chiral stationary phases (CSPs). Chiral columns of Astec CYCLOBOND^TM I 2000 series, such as the native β-cyclodextrin (Cyclobond I 2000), acetyl-β-cyclodextrin (AC-β-CD), 2,3-dimethyl-β-cyclodextrin (DM-β-CD) and 3,5-dimethylphenyl carbamate β-cyclodextrin (DMP-β-CD), were examined under the reversed-phase mode. The effects of cyclodextrin stationary phase, mobile phase composition, pH, flow rate and column temperature on the separation of milnacipran enantiomers were investigated. The inclusion process between AC-β-CD and milnacipran enantiomers was investigated and chiral recognition mechanism was studied with molecular docking technique and binding energy calculations. The optimized conditions were as follows: the chiral stationary phase was a column of Astec CYCLOBOND^TM I 2000 AC (25 cm×4.6 mm, 5 μm), the mobile phase was acetonitrile-0.1% (v/v) pH 5.0 triethylamine acetate (TEAA) (5:95, v/v) with a flow rate of 0.4 mL/min and the detection wavelength was 220 nm. The injection volume was 10 μL and the column temperature was 25℃. The value of resolution (R_s) was 1.74 and the theoretical plates were 10125. The results suggested that hydrogen bonding ability played an important role in the chiral recognition process of milnacipran enantiomers. The developed method was rapid, effective and reproducible.