Lee Kayoung, Shin Sang-Chul, Oh Injoon
College of Pharmacy and Research Institute of Drug Development, Chonnam National University, Korea.
Arch Pharm Res. 2003 Aug;26(8):653-8. doi: 10.1007/BF02976716.
It has been reported that at low temperature region, poloxamers existed as a monomer. Upon warming, an equilibrium between unimers and micelles was established, and finally micelle aggregates were formed at higher temperature. In this study, the fluorescence spectroscopy was used to study the micelle formation of the poloxamer 407 in aqueous solution. The excitation and emission spectra of pyrene, a fluorescence probe, were measured as a function of the concentration of poloxamer 407 and temperature. A blue shift in the emission spectrum and a red shift in the excitation spectrum were observed as pyrene transferred from an aqueous to a hydrophobic micellar environment. From the I1/I3 and I339/I333 results, critical micelle concentration (cmc) and critical micelle temperature (cmt) were determined. Also, from the fluorescence spectra of the probe molecules such as 8-anilino-1-naphthalene sulfonic acid and 1-pyrenecarboxaldehyde, the blue shift of the lambdamax was observed. These results suggest a decrease in the polarity of the microenvironment around probe because of micelle formation. The poloxamer 407 above cmc strongly complexed with hydrophobic fluorescent probes and the binding constant of complex increased with increasing the hydrophobicity of the probe.
据报道，在低温区域，泊洛沙姆以单体形式存在。升温时，单分子与胶束之间建立平衡，最终在较高温度下形成胶束聚集体。在本研究中，采用荧光光谱法研究泊洛沙姆407在水溶液中的胶束形成。作为荧光探针的芘的激发光谱和发射光谱随泊洛沙姆407浓度和温度的变化而测定。当芘从水相转移到疏水胶束环境时，观察到发射光谱蓝移和激发光谱红移。根据I1/I3和I339/I333结果，确定了临界胶束浓度（cmc）和临界胶束温度（cmt）。此外，从8-苯胺基-1-萘磺酸和1-芘甲醛等探针分子的荧光光谱中，观察到最大波长的蓝移。这些结果表明，由于胶束形成，探针周围微环境的极性降低。高于cmc的泊洛沙姆407与疏水荧光探针强烈络合，络合物的结合常数随探针疏水性的增加而增大。
