Strukturuntersuchungen von Salben 2. Mitteilung: Strukturuntersuchungen an der Wasserhaltigen Hydrophilen Salbe DAB 7
H. Junginger , C. Führer , J. Ziegenmeyer , S. Friberg

Synopsis

X-ray investigation by the Kiessig low-angle technique and by goniometry were carried out in order to characterize the crystalline gel backbone of water-containing hydrophilic ointment DAB 7 and of its components. Cetyl-stearyl alkohol — independent of the water content of the system — forms a semihydrate by interlamellar incorporation of water with minimal lattice enlargement. In the case of emulsifying cetyl-stearyl alcohol DAB 7, on the other hand, the incorporation of water molecules between the polar groups causes considerable enlargement of the lamellar structure as a function of the water content of the total system. Similar results were obtained for water-containing hydrophilic ointment DAB 7. These hydrates form discrete, sharp, endothermic peaks within the temperature range of 68 to 72°C during differential scanning calorimetry, both in the case of emulsifying cetyl-stearyl alcohol DAB 7 and in the case of water-containing hydrophilic ointment DAB 7. A cream of the o\/w type, therefore, consists of two components: One is the three-dimensional, crystalline, viscosity forming gelled backbone component of the total system which is highly swollen by water incorporation. The other is a discontinuous phase of lipophilic components (white vaseline and viscous paraffins) which is primarily mechanically immobilized by incorporation into the gelled backbone structure. The external continuous phase comprises that portion of the water which is not incorporated into the gel backbone but is, nevertheless, in direct equilibrium with it.

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