Prediction of Emulsion Stability: Facts and Myth
V. André, N. Willenbacher, H. Debus, L. Börger, P. Fernandez, T. Frechen, J. Rieger¹; Cosmetics and Toiletries Manufacture Worldwide (2003) pp.102-109, Aston Publishing Group, Florida.
Abstract: The achievement of long time stability of cosmetic products (3 years shelf life) is a difficult and costly step in the development of new formulations. Stability is also one of the first conditions that has to be respected when one wishes to develop new ingredients (after toxicity and cosmetic elegance). However, it remains a very tedious procedure to determine stability because many formulations are first prepared, then stored at various temperature and analysed during storage. The aim of this work is to show that it is possible to reduce the amount of formulations stored and storage time - and therefore reduce costs and time - by analysing potential instabilities at a very early stage, namely, 24 hours after the formulation has been prepared. Besides, in the search for new basis formulation it can be helpful to test only a part of the formulation (not all the components together, only a few chosen ones) and see how the system behaves without having to store a complete sample. However since many factors can lead to instabilities1 and these factors are not always easy to identify, several analytical methods are necessary in order to represent an unambiguous diagnostic tool. These methods are not always available to every formulator, therefore it is useful for a supplier to achieve an in-depth understanding of raw materials in regard of the formulation stabilities. The idea is, of course not, to formulate as broadly as our customers but to work on a basis that can be used for further improvements of the raw materials. One aim of this work was to gain a better understanding of the role of pigments in the stability of emulsion and to learn if there is a possibility of being able to predict the related stability in a reliable manner.
Key words: Emulsion stability • Shelf life • Pigment stabilized emulsion • Zinc Oxide • Oil in water emulsion • Titanium dioxide • Accelerated stability test • LUMiFuge
¹ Institut für Mechanische Verfahrenstechnik und Mechanik, University of Karlsruhe, Karlsruhe, Germany.Contact us
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