Various emulsion types have been developed throughout the history of the cosmetic industry. Due to their ability to solubilize relatively large amounts of water-insoluble ingredients, i.e., emollients and fragrances, and provide long-term stability, microemulsions have been a suitable vehicle in various skin care applications. Microemulsions have long assisted the pharmaceutical industry in delivering efficacious levels of an active ingredient to the skin by enhancing the active’s bioavailability, versus traditional solutions and dispersions.1 An example of this technology is seen in the immunosuppressant drug cyclosporina, commonly used to treat psoriasis and rheumatoid arthritis.
These novel vehicles soon made their transition for many skin care applications, where they provide luxurious aesthetics as well as outstanding stability. The benefit of these microemulsions has been identified for various skin care applications such as moisturization, cleansing, sunscreen and antiperspirants. Their advantage over conventional formulations to introduce lipophilic and hydrophilic actives to the skin or hair has proved to be beneficial.