Lv Xia, Zhang Shuguang, Ma Huipeng, Dong Peipei, Ma Xiaodong, Xu Ming, Tian Yan, Tang Zeyao, Peng Jinyong, Chen Haibo, Zhang Jianbin
College of Pharmacy, Dalian Medical University, Dalian 116044, China.
College of Life Science, Dalian Minzu University, Dalian 116600, China.
Acta Pharm Sin B. 2018 Jul;8(4):655-665. doi: 10.1016/j.apsb.2018.05.008. Epub 2018 May 23.
Microemulsions are promising drug delivery systems for the oral administration of poorly water-soluble drugs. However, the evolution of microemulsions in the gastrointestinal tract is still poorly characterized, especially the structural change of microemulsions under the effect of lipase and mucus. To better understand the fate of microemulsions in the gastrointestinal tract, we applied small-angle X-ray scattering (SAXS) and fluorescence resonance energy transfer (FRET) to monitor the structural change of microemulsions under the effect of lipolysis and mucus. First, the effect of lipolysis on microemulsions was studied by SAXS, which found the generation of liquid crystalline phases. Meanwhile, FRET spectra indicated micelles with smaller particle sizes were generated during lipolysis, which could be affected by CaCl, bile salts and lecithin. Then, the effect of mucus on the structural change of lipolysed microemulsions was studied. The results of SAXS and FRET indicated that the liquid crystalline phases disappeared, and more micelles were generated. In summary, we studied the structural change of microemulsions in simulated gastrointestinal conditions by SAXS and FRET, and successfully monitored the appearance and disappearance of the liquid crystalline phases and micelles.
微乳剂是用于口服难溶性药物的很有前景的给药系统。然而，微乳剂在胃肠道中的演变仍未得到充分表征，尤其是在脂肪酶和黏液作用下微乳剂的结构变化。为了更好地了解微乳剂在胃肠道中的命运，我们应用小角X射线散射（SAXS）和荧光共振能量转移（FRET）来监测脂肪分解和黏液作用下微乳剂的结构变化。首先，通过SAXS研究了脂肪分解对微乳剂的影响，发现了液晶相的产生。同时，FRET光谱表明在脂肪分解过程中生成了粒径较小的胶束，其可能受到氯化钙、胆汁盐和卵磷脂的影响。然后，研究了黏液对脂肪分解后的微乳剂结构变化的影响。SAXS和FRET的结果表明液晶相消失，并且生成了更多的胶束。总之，我们通过SAXS和FRET研究了模拟胃肠道条件下微乳剂的结构变化，并成功监测了液晶相和胶束的出现和消失。
