Delivery systems are equally crucial as the active ingredients in a cosmetic formulation. In fact, active ingredients must be targeted to their optimal site of action through the skin barrier to achieve their beneficial actions. Moreover, very often, active ingredients are extremely sensitive to physical (light, UV radiation, heat) and chemical (oxidation, sensitiveness to acids or bases, etc.) degradation and require to be stabilised in the formulation in order to ensure that they retain their efficacy. In addition to that, if more actives are included in a formulation it could become crucial to avoid them from interacting before their effective use. Another problem could be represented by the fact that actives could not be directly soluble in the formulation. Finally, active ingredients could have unpleasant side effects or properties (e.g. cause irritation, have a bad odour give an unpleasant coloration, etc.) and must be masked in the final formulation.
Delivery systems are used to address and solve all these potential formulation issues. They incorporate, stabilise, protect, solubilise, mask and, last but not least, correctly target through the skin barrier the active ...