奥拉西坦光学对映体在多糖类手性固定相上的拆分

Separation of oxiracetam optical enantiomers using polysaccharide chiral stationary phase

目的:采用多糖类手性固定相,建立了奥拉西坦光学对映体的HPLC手性分析方法。方法:考察5种手性柱、流动相的组成、温度和流速对奥拉西坦光学对映体色谱行为(半峰宽、分离度、容量因子k’、选择因子α和理论板数)的影响。结果:获得的最佳分离条件为:色谱柱为Chiralpak AS-H手性柱(250 mm×4.6 mm),流动相为正己烷-0.1%二乙胺乙醇溶液(80∶20),流速0.5 mL·min-1,柱温38℃。实验数据表明,提高流动相中的乙醇比例可以缩短分析时间,提高柱效,但是会降低手性选择性;提高柱温有助于改善峰形,提高柱效和增加手性选择性;降低流速可以通过影响柱效来提高分离度。结论:建立了一种快速准确拆分奥拉西坦光学对映体的体外分析方法,实现了奥拉西坦光学对映体的完全分离,并测定了合成的(S)-和(R)-奥拉西坦的光学纯度。

Objective： To establish an HPLC method for chiral separation and analysis of oxiracetam optical enantiomers using polysaccharide chiral stationary phase. Methods： The effects of columns,composition of mobile phase,column temperature and flow rate on the chromatographic behavior were investigated. Results： The separation condition was optimized：using Chiralpak AS-H as chiral column,n-hexane-ethanol containing 0.1% diethylamine（80：20） as mobile phase,with a flow rate at 0.5 mL·min^-1 and 38 ℃ as column temperature.The experimental data showed that higher ethanol content in mobile phase could shorten analysis time and improve column efficiency,but it also reduced chiral selectivity;higher column temperature could make important contribution to narrowing peak shape,improve column efficiency and increase chiral selectivity;lower flow rate can improve resolution by affecting column efficiency. Conclusion： An in vitro analysis method is developed that can enantioseparate oxiracetam rapidly and reliably,and the values of enantiomeric excess of （S）-oxiracetam and （R）-oxiracetam are determined successfully,which are more than 97% and 95%,respectively.