Spectrophotometric investigation of the binding of vitamin E to water-containing reversed micelles.
The distribution constants of vitamin E partitioned between apolar organic phase and water-containing reversed micelles of sodium bis (2-ethylhexyl) sulfosuccinate (AOT), didodecyldimethylammonium bromide (DDAB), soybean phosphatidylcholine (lecithin) and tetraethylene glycol monododecyl ether (C12E4) have been evaluated by a spectrophotometric method. The results suggest that in the presence of domains from apolar organic solvent to surfactant and to water, vitamin E is partitioned between the micellar palisade layer and the organic solvent and also that its binding strength to reversed micelles depends mainly by specific interactions between the head group of vitamin E and that of the surfactant. Moreover, in addition to the advantageous interactions between vitamin E and water, the dependence of the distribution constants upon the molar ratio R (R=[water]/[surfactant]) indicates a competition between water and vitamin E for the binding sites at the water/surfactant interface. The biological implications of the preferential location and confinement of vitamin E in water-containing reversed micelles are discussed.
Avellone
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G
Dipartimento di Chimica e Tecnologie Farmaceutiche, Via Archirafi 32, 90123 Palermo, Italy.
Bongiorno
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D
Ceraulo
L
L
Ferrugia
M
M
Turco Liveri
V
V
D000465:Algorithms; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004143:Dioctyl Sulfosuccinic Acid; D008823:Micelles; D010713:Phosphatidylcholines; D000644:Quaternary Ammonium Compounds; D013056:Spectrophotometry, Ultraviolet; D013501:Surface-Active Agents; D014810:Vitamin E / Q000737:chemistry*; D014867:Water
D008823:Micelles; D010713:Phosphatidylcholines; D000644:Quaternary Ammonium Compounds; D013501:Surface-Active Agents; D014867:Water; D004143:Dioctyl Sulfosuccinic Acid; C046112:didodecyldimethylammonium; D014810:Vitamin E