Organ
of the
GD — Society for Dermopharmacy
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Issue 2 (2002) |
Dermocosmetics
Novel Gel Systems
Multiple Applications in Dermocosmetics
Besides creams and lotions gels are important as basis of cosmetical and dermatological topical preparations. A distinction is made between clear to opaque hydro-gels, hydro-dispersion gels with creamy appearance and water-free oleo gels. There are numerous new developments of each formulation type offering benefits relating to their physico-chemical and skin physiological properties.
Professor Dr. Rolf Daniels, Institut für Pharmazeutische Technologie (Institute for Pharmaceutical Technology), Brunswick University informed in a lecture at the GD symposium "Effects of Dermocosmetics" about the application potential of these gel systems in Düsseldorf on 17 October 2001. From a physico-chemical point of view, these gels are disperse systems, consisting of at least two components - a solid component and a liquid. The solid component forms a coherent, three-dimensional structure whereas the liquid is present in an immobilized form as coherent medium in the matrix.
Water-free Oleo Gel
Oleo gels consist of a lipophile liquid phase. As gel former besides bentonite and silica, a special copolymer compound has been recently applied. It forms together with liquid lipids highly transparent clear gels, which are qualified as basis for a large range of cosmetic formulations. As the viscosity of these formulations decreases in the sphere of the skin temperature, an even spreading of the products on skin is enhanced. In contrast to its lipid phases, oleo gels have a higher substantivity with longer lasting reduction of the trans-epidermal water loss. Moreover, they have good stabilizing properties for suspensions and prevent sedimentation of solids, such as zinc oxides even at higher temperatures.
Hydro-dispersion Gels
Hydro-dispersion gels consist of a hydrophilic continuous and a lipophile disperse phase. Hydro-dispersion gels at which hypromellosis instead of the applied polyacrylates or polyacrylates/polyalkyl-cross polymers are used as standard gel former open up new perspectives. This gel former allows the production of hydro-dispersion gels with particle sizes in the sub-micron area to which both alcohol and electrolytes can be fed. Nano emulsions stabilized with hypromellosis can be sprayed without difficulties and sterilized without quality loss in the final container, the latter opening up the possibility of avoiding the use of preservatives. (jk)
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Additional information about the contents of the lecture held by Professor Dr. Rolf Daniels at the GD Symposium "Effects of Dermocosmetics" in Düsseldorf on 17 October 2001 is contained in the English issue 2/2002 of the E-Journal of DermoTopics (www.dermotopics.com) under the title "Novel Gel Systems". |