ISSN:
1573-904X
Keywords:
nonionic surfactants
;
Macrogolstearate 400
;
lamellar phase
;
hydrophilic creams
;
gel-liquid crystalline phase separation
;
nonionic surfactant vesicles
;
cationic surfactant vesicles
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract In binary Macrogolstearate 400 (MS 400)/water systems, lamellar surfactant arrangements can be detected by polarized light and transmission electron microscopy. As demonstrated by X-ray diffraction and differential scanning calorimetry, the alkyl chains of the emulsifier are in the crystalline state. Ternary systems with liquid paraffin represent optically isotropic, homogeneous o/w creams for a wide composition range. Incorporation of up to 50 mol% cholesterol into the MS 400 lamellar structures leads to a gel-liquid crystalline phase separation within the bilayer, thus enabling the formation of spherical nonionic vesicles. The transition enthalpy of the samples decreases linearly with increasing cholesterol concentrations. The Macrogolstearate 400/cholesterol vesicles proved to be stable in hydrophilic cream systems. Cationic vesicles can be prepared using cetyltrimethylammonium bromide (CTAB) as a charge inducer. Low-CTAB portions are inhomogeneously distributed within the bilayer, as detected by DSC. The results also indicate a perturbation of the alkyl chains packing for the positively charged vesicles.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1015821821009
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