氧氟沙星包合物的制备、表征及其包合机制的分析

目的：研究氧氟沙星与环糊精（包括β-环糊精和羟丙基β-环糊精）包合物的制备过程，包合物的结构表征以及包合机制。方法：采用超声法制备包合物，并采用各种不同的方法对形成的包合物进行表征和识别，包括荧光光谱法、紫外-可见分光光度法和核磁共振法等。荧光光谱法计算包合常数（K）以及包合比（n），同时研究室温条件下不同浓度的环糊精及其衍生物以及不同的酸碱度对包合作用的影响，核磁共振法用于研究包合机制。结果：溶液中不同的pH对氧氟沙星的存在形式影响不同；不同pH条件下，环糊精对氧氟沙星具有不同的包合能力，其中β-环糊精（β-CD）在中性条件下更容易与氧氟沙星进行包合，其包合常数为1 300；而羟丙基β-环糊精（HP-β-CD）更容易在酸性性条件下与氧氟沙星进行包合，其包合常数为1 640。在研究的浓度范围内，环糊精分子与氧氟沙星分子是按1：1形成包合物的。结论：氧氟沙星与环糊精在实验条件下形成了稳定的包合物，氧氟沙星分子是从环糊精及其衍生物的大口端包合进入到空腔内。

Preparation,characterization and inclusion mechanism of ofloxacin inclusion complex and analysis of their inclusion mechanism

OBJECTIVE To study the preparation of inclusion complexes of ofloxacin with cyclodextrins,(including beta-cyclodextrin and hydroxypropyl beta-cyclodextrin) in solution, the structural characterization and the inclusion mechanism. METHODWS The inclusion complexes were prepared by ultrasonic method and identified by various methods, including fluorescence spectroscopy, ultraviolet-visible spectrophotometer and nuclear magnetic resonance. The inclusion constant (K) and inclusion ratio (n) were calculated by fluorescence spectroscopy. The effects of different concentration of cyclodextrins and different pH values on inclusion were studied at room temperature. The inclusion mechanism of cyclodextrin and ofloxacin was confirmed by NMR. RESULTS Different pH values in the solution had different effects on the existing forms of ofloxacin; under different pH conditions, the cyclodextrins had different inclusion ability for ofloxacin, in which β-cyclodextrin (β-CD) was easier to be included with ofloxacin under neutral conditions, and its inclusion constant was 1 300; while hydroxypropyl β-cyclodextrin (HP-β-CD) was easier to be included with ofloxacin under acidic conditions, and its inclusion constant was 1 640. In the concentration range used in this study the complexation ratio was 1:1. CONCLUSION Ofloxacin and cyclodextrin form a stable inclusion complex under the experimental conditions. Ofloxacin molecules enter the cavity from the bulky end of cyclodextrin and its derivatives.