ISSN:
1435-1536
Keywords:
Polyoxyethylene cholesteryl ethers
;
liposome
;
membrane-lysis
;
membrane fluidity
;
activation energy
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract In order to deduce the mechanisms of hemolysis induced with the nonionic surfactants, polyoxyethylene cholesteryl ethers, C27H45(OCH2CH2) n OH (n=8, 25, 30, 50) and polyoxyethylene dihydrocholesteryl ethers, C27H47(OCH2CH2) n OH (n=15, 30, 50), the interaction of these surfactants with the liposomal membrane as a simple model membrane was investigated in terms of a leakage of the entrapped marker, and a change of the membrane fluidity. The time-courses of the marker leakage were characterized with two kinetic parameters, the initial induction period and the apparent first-order rate constant. The polyoxyethylene chain length was an important factor in the membrane-lytic activities, and the maximal rate as well as the maximal amount of the marker leakage was observed with n=25–30 in these surfactants series. However, the apparent activation energies derived from the two kinetic parameters increased almost linearly with the hydrophilic chain length. The used surfactants tended to fluidize the liposomal membrane in the concentration ranges of surfactants where the marker leakage is not at all or only slightly induced — but with the higher concentration of the cholesteryl derivatives, the apparent fluidity was significantly reduced. From these observations, the mechanisms of the membrane-lysis are discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01410576
