荧光光谱法研究左氧氟沙星与MCM-41的相互作用

采用微波辅助水热法制备介孔分子筛MCM-41,并用浸渍法将左氧氟沙(LVFX)组装在MCM-41均一的六方形孔道中,制备出新型载药复合物LVFX/MCM-41.用粉末X射线衍射(XRD)、低温氮吸附、傅里叶变换红外光谱(FTIR)及差热-热重(TGA-DTA)分析对MCM-41以及LVFX/MCM-41复合物进行表征,合成的介孔分子筛MCM-41的孔径为2.382 nm,比表面积为1 015 m2·g-1.对MCM-41、LVFX/MCM-41、LVFX(固态)及LVFX(溶液)的荧光光谱研究结果显示,LVFX/MCM-41的荧光光谱比组装前发生明显红移,表明MCM-41孔道内表面的羟基和LVFX形成氢键,羟基上的电子云向LVFX分子上的吸电子基团转移;同时MCM-41和LVFX之间形成新环,使电子云能在更大的环上移动,药物分子的共轭体系扩大,荧光光谱峰红移.MCM-41与左氧氟沙星之间强的相互作用为研发以MCM-41为载体的新型释药系统提供了理论依据.

Study on the Interaction of Levofloxacin and MCM-41 by Fluorescence Spectrum

The mesoporous molecular sieve MCM-41 was synthesized by hydrothermal method under microwave irradiation and the levofloxacin was encapsulated in the hexagonal ordered channels of MCM-41 using pickling process. The structure and property of MCM-41 and LVFX/MCM-41 were characterized by means of small-angle X-ray diffraction（XRD）, Fourier transform infrared spectroscopy (FTIR), N2 physical adsorption， and thermogravimetric analysis-differential thermal analysis （TGA-DTA）. The pore diameter and the specific surface area of the mesoporous molecular sieve MCM-41 synthesized under microwave irradiation were 2.382 nm and 1 015 m2·g-1 respectively. The fluorescence spectra of MCM-41, LVFX/MCM-41, LVFX （solid） and LVFX （solution） were investigated. The results indicated that there were some visible red shifts in the fluorescence spectrum of the composite of LVFX/MCM-41 as compared with the samples before being encapsulated. It was inferred from the results that hydrogen bonds were formed between levofloxacin and the hydroxy group in the inner pores, and the electron cloud could transfer from the hydroxy group to electro-attracting group. At the same time, the electron cloud could transfer in much larger annulations, and the conjugated system of LVFX was extended because of the new annulations formed, which contributed to the red shifts of the fluorescence spectra. The strong interactions between the LVFX and MCM-41 provided the theory for developing a novel delayed release drug using MCM-41 as the carriers.