ISSN:
1572-8927
Keywords:
Solubilization
;
liposome
;
partition coefficient
;
phase transition
;
ω-phenylalkanols
;
dipalmitoylphosphatidylcholine (DPPC)
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The gel-to-liquid-crystalline phase transition temperature T m of dipalmitoylphosphatidylcholine (DPPC) liposome membrane was measured in the presence of homologous ω-phenylalkanols (phenol to 8-phenyl-1-octanol). The decrease in T m induced by the alkanols allowed us, by applying the van't Hoff equation for freezing-point depression, to estimate two partition coefficients of each alkanol: gel membrane/bulk water K x g and liquid-crystalline membrane/bulk water K x 1 . Shorter alkyl chain alkanols were solubilized only in the liquid-crystalline membrane, i.e., K x g =0, whereas longer-chain alkanols were solubilized not only in the liquid-crystalline membrane but also in the gel membrane. The former result suggests that the fraction of liquid-crystalline phase in the liposome membrane is 0.83 at T m. From the latter result, the values of the free energy changes of transfer of the alkanol molecules from bulk water to liposome membrane were estimated to be − 3.46 kJ-mol−1 (liquid-crystalline membrane) and − 3.85 kJ-mol−1 (gel membrane) per CH2 group in the alkanol molecules.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1021736632360
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