Participation of Macrogolstearate 400 lamellar phases in hydrophilic creams and vesicles.
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.
Paspaleeva-Kühn
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V
Cosmetic Research and Development Department, Merz & Co., Frankfurt am Main, Germany.
Nürnberg
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E
D002152:Calorimetry, Differential Scanning; D000077286:Cetrimonium; D002593:Cetrimonium Compounds; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002784:Cholesterol / Q000737:chemistry; D005079:Excipients; D008567:Membranes, Artificial; D008855:Microscopy, Electron, Scanning; D009824:Ointments; D011092:Polyethylene Glycols / Q000737:chemistry*; D013501:Surface-Active Agents / Q000737:chemistry*; D014961:X-Ray Diffraction
D002593:Cetrimonium Compounds; D005079:Excipients; D008567:Membranes, Artificial; D009824:Ointments; D013501:Surface-Active Agents; D011092:Polyethylene Glycols; C009314:polyethylene glycol monostearate; D002784:Cholesterol; D000077286:Cetrimonium