The inclusion of, for example, sunscreens in hair care products is of great interest because of the potential to reduce damage such as drying and loss of elasticity and also to reduce the fading of color-treated or bleached hair. For a variety of reasons traditional methods of incorporation of UV filters have often proved difficult and, at best, unsatisfactory; the need for additional solubilizers, changes in residual feel, rinse out, incomplete wetting and poor affinity have all been noted and observed.
Furthermore, traditional hair conditioning formulations are sensitive to any processing conditions which might affect the size and distribution of the dispersed conditioning agent (1). In formulations containing silicone or hydrocarbon oil the performance is influenced by the nature of the emulsifying system and the extent to which any cationic substituents modify the physical and chemical characteristics of the oil phase. Thus, an important pre-requisite is that any additional component must not adversely affect the conditioner composition nor inhibit the conditioning behavior.
Particle Sciences’ proprietary microencapsulation technology is an adaptation of a physical methodology; however, the average particle size is an order of magnitude smaller, typically from 0.1 to 1.0 micron (Figure 1). These nanoparticles are a homogeneous mixture of matrix and active dispersed in water. Because of their extremely small size, the nanoparticulates are easily incorporated into virtually any kind of delivery system; being encapsulated, the organic actives can then be delivered in systems formerly unacceptable or hostile to them. The particles can be designed for controlled release, or, as this example for sunscreen actives, no release (2).