Active research continues in the area of delivery systems for cosmetic products. Particulate delivery systems such as liposomes, which are tiny, hollow lipid spheres, are used to carry active ingredients into the skin. However, smaller, more specialized transportation systems are being developed; these include nanoparticles, microcapsules, and millicapsules.
Nanotechnology is making its way to the forefront of the cosmetic industry. Nanoparticles are solid hydrophobic spheres with an average particle size of less than one micron; they have high cationic charge density to improve their deposition onto the target site and prevent them from being washed off during rinsing (22). This bioadhesive quality also reduces the need for reapplication. The hydrophobic quality of the nanospheres sustains the diffusion rate of the active ingredients, which allows their release over an extended period of time. The nanospheres have improved stability when compared with emulsion – based delivery systems, such as liposomes. This enhanced stability prolongs product shelf life. In addition, the substance to be delivered does not have to be soluble in the vehicle, since it can be dispersed in the solid matrix. Incorporating an ingredient such as a sunscreen into nanoparticles in a skin care product allows the product to block UV light, but does not interfere with the look and feel of the lotion. As nanotechnology advances, it may enable the development of more customized and effective personal care products.
