Organogels from 1H-Imidazole Amphiphiles: Entrapment of a Hydrophilic Drug into Strands of the Self-Assembled Amphiphiles

Linear 1 H -imidazole amphiphiles ( 1 − 3 ) were synthesized by the esterification reaction of 4‘-alkyloxy phenol with 4-chlorocarbonyl imidazole. They formed organogels. When 1 N of the imidazole head was blocked by an ethyl group, however, the compound ( 4 ) did not self-assemble. The SAX and TEM study revealed that in a dry gel state, the 1 H -imidazole amphiphiles self-assembled into a fibrous aggregate having a reverse micellar cubic structure. Norfloxacin (NFLX), a fluorescent hydrophilic antibiotic, showed relatively weak fluorescence emission in THF/ n -hexane (10 -6 mol/mL) when excited at 280 nm. In the organogel of compound 3 (1.5 wt %) in THF/ n -hexane, integrated fluorescence intensity of NFLX was enhanced approximately 10 times as compared to that in the THF/ n -hexane solution or sol state, strongly suggesting that NFLX was trapped in the hydrophilic core of a micellar assembly of compound 3 . The dry gel fibers were also strongly fluorescent under confocal laser scanning microscopy.