Host-guest interactions of 5-fluorouracil in supramolecular organogels.
Supramolecular organogels were formed by the self-assembly of gelator 1,3:2,4-di-O-benzylidene-d-sorbitol (DBS) in 1,2-propylene glycol. 5-Fluorouracil (5-Fu) was entrapped in the organogels as guest molecules. Field-emission scanning electron microscopic measurements of the organogels indicate that the diameters of the fibrillar aggregates formed by DBS self-assembly were in the range of 20-70 nm. The host-guest interactions between 5-Fu and supramolecular gel matrix were investigated by using temperature-dependent differential UV spectroscopy and differential scanning calorimetry. The red shifts of the absorption band of 5-Fu in the organogels are indicative of the interaction between 5-Fu and DBS. The red shifts were enhanced upon decreasing the temperature. Calculation of optimized geometries revealed the formation of hydrogen bonds between 5-Fu and DBS aggregates. The analysis of differential scanning calorimetric data for the organogels with and without 5-Fu further showed that the self-assembly of DBS was interfered by the 5-Fu in the organogels, resulting in a decrease in the dissociating temperature of DBS aggregates.
Wang
Hong
H
School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan, China.
Zhang
Jinye
J
Zhang
Weiping
W
Yang
Yajiang
Y
D002152:Calorimetry, Differential Scanning; D002626:Chemistry, Pharmaceutical / Q000379:methods; D005472:Fluorouracil / Q000008:administration & dosage*; D005782:Gels; D008855:Microscopy, Electron, Scanning / Q000379:methods; D010316:Particle Size; D019946:Propylene Glycol / Q000737:chemistry*; D013012:Sorbitol / Q000031:analogs & derivatives* / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature
D005782:Gels; D013012:Sorbitol; D019946:Propylene Glycol; D005472:Fluorouracil; C097391:dibenzylidene sorbitol