Relative affinity of 5-methoxypsoralen and 8-methoxypsoralen towards beta-cyclodextrin: a fluorescence, circular dichroism and chromatographic study.
The relative affinity of 5-methoxypsoralen (5-MOP) and 8-methoxypsoralen (8-MOP) towards beta-cyclodextrin, a good model for the study of lipophilic interactions in biological systems and a potential drug carrier, has been investigated using spectroscopic and chromatographic methods. The fluorescence emission of 5-MOP in aqueous solution containing beta-cyclodextrin (10(-2) M) is found to be markedly blue shifted and enhanced by a factor of 6 whereas no significant changes are observed for 8-MOP. The existence of an induced circular dichroism is evidence for the formation of a 1:1 inclusion complex (association constant K = 400 +/- 50 M-1). Moreover, chromatographic results obtained with a beta-cyclodextrin linked stationary phase are consistent with our spectroscopic results and might have interesting analytical implications. These results clearly demonstrate that, in contrast to 8-MOP, 5-MOP exhibits a strong affinity for hydrophobic medium. Interesting pharmacological and analytical applications may result from the possible inclusion of psoralen derivatives into beta-cyclodextrin.
Blais
J
J
Laboratoire de Physique et Chimie Biomoléculaire (CNRS UA 198), Institut Curie et Université PARIS VI, France.
Prognon
P
P
Mahuzier
G
G
Vigny
P
P
D000078223:5-Methoxypsoralen; D055598:Chemical Phenomena; D002621:Chemistry; D002942:Circular Dichroism; D003505:Cyclodextrins; D003912:Dextrins; D004337:Drug Carriers; D007536:Isomerism; D008730:Methoxsalen; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry; D013213:Starch; D013329:Structure-Activity Relationship; D047392:beta-Cyclodextrins
D003505:Cyclodextrins; D003912:Dextrins; D004337:Drug Carriers; D047392:beta-Cyclodextrins; D000078223:5-Methoxypsoralen; D013213:Starch; C031215:betadex; D008730:Methoxsalen