The trend for multifunctional products that supply multiple benefits with minimal effort is driving the innovation of a new generation of cosmetic delivery systems, according to a recent article published in the International Journal of Cosmetic Science. Indeed, the US market for delivery systems has increased from $19bn in 2000 to over $41bn in 2007, according to the report. The authors, V.B. Patravale and S.D. Mandawgade, refer to a new generation of active ingredients that form the basis of many novel multifunctional products and the problems they pose for formulators. "With these emerging actives, come a range of formulation challenges that includes stability control and the complications of combining several actives into a single cosmetic product," they explained. Liposome encapsulation of actives Liposomes and nanoemulsions are believed to have a great future in the cosmetic delivery systems, according to the authors, who also cite cosmetic patches as having great potential for the future. Liposomes are used to encapsulate ingredients and facilitate their transfer across the skin barrier thereby solving some of the stability challenges experienced when using certain actives. Furthermore, multiple ingredients can be encapsulated and included in the same formulation without danger of reactions between the ingredients. New encapsulation technologies will also play a role in one of the most important future delivery trends, namely the controlled release of actives. Release modulated by temperature and pH Systems that release their actives over a sustained period of time are likely to become increasingly prevalent in the industry, according to the report. "Some trends that the consumer is likely to see in the future include improved systems that release their active via pH and temperature modulation," they write. The authors go on to reference the advances that have been made in nanotechnology and the use of nanoemulsions in cosmetics formulations. Nanoemulsions are valued because of their sensorial properties such as rapid penetration and their biophysical properties, state the authors. In addition, cosmetic patches are expected to become increasingly popular in the products of tomorrow as they can deliver potent ingredients quickly and effectively, state the authors.