Influence of the Homogenisation Time on the Physical Properties of an o/w Cream Anja Grossmann1, 2, Enrico Ceruti2, Fausto Cadei2, Alessandro Regola2, and Rolf Daniels3 1 Schering AG Berlin, Berlin (Germany) Corresponding author: Prof. Dr. Rolf Daniels, Institut für Pharmazeutische Technologie, Eberhard-Karls-Universität Tübingen, Auf der Morgenstelle 8, 72076 Tübingen (Germany), e-mail: rolf.daniels@uni-tuebingen.de The final homogenisation step during cream preparation affects directly and almost irreversibly the microstructure of the investigated o/w cream and thus its physical properties. A relationship between time of homogenisation and water distribution in the cream could be shown. With increasing shearing the water binding capacity of the lamellar gel phase decreases. This was demonstrated by increased syneresis, electrical conductivity and a higher fraction of free water. Further, the disorganisation of the microstructure leads to changes in the rheological behaviour. Increasing shearing during final homogenisation lowers the apparent shear viscosity and reduces the hysteresis area of the cream. A final homogenisation during cream preparation downgrades the cream quality and hence should be limited to the minimum time and shear necessary. Key words Creams, homogenisation time, manufacturing process parameters, physical properties • Semi-solid drug forms • Topical o/w creams |
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pharmind 2007, Nr. 6, Seite 730