Cyclodextrins as carriers for cinchona alkaloids: a pH-responsive selective binding system.
A series of cyclodextrin-cinchona alkaloid inclusion complexes were prepared from beta-cyclodextrin, heptakis(2,6-di-O-methyl)-beta-cyclodextrin and heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin and four cinchona alkaloids in ca. 90% yields, and their inclusion complexation behavior was investigated at pH 7.2 and 1.5 by means of fluorescence, UV/Vis and 2D NMR spectroscopy. The results showed that the cinchona alkaloids can be efficiently encapsulated in the cyclodextrin cavity in an acidic environment and sufficiently released in a neutral environment, which makes these cyclodextrin derivatives the potential carriers for cinchona alkaloids. The binding ability and molecular selectivity of cyclodextrins toward cinchona alkaloids were discussed from the viewpoint of the size-fit concept and multiple recognition mechanism between host and guest.
Liu
Yu
Y
Department of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, PR China. yuliu@public.tpt.tj.cn
Chen
Guo-Song
GS
Chen
Yong
Y
Ding
Fei
F
Chen
Jing
J
D001665:Binding Sites; D002930:Cinchona Alkaloids / Q000737:chemistry* / Q000378:metabolism; D003505:Cyclodextrins / Q000737:chemistry* / Q000378:metabolism; D004337:Drug Carriers / Q000737:chemistry* / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D015394:Molecular Structure; D013057:Spectrum Analysis
D002930:Cinchona Alkaloids; D003505:Cyclodextrins; D004337:Drug Carriers