Formulation effects in percutaneous absorption

Formulation optimisation is one of the strategies used for optimising delivery into or through the skin. In addition to ensuring that an active chemical is delivered at an adequate rate to achieve therapeutic concentrations over the intended duration, physicochemical formulation stability as well as product acceptance must also be achieved. There is a continual growth in new potential delivery systems, such as microemulsions, liposomes, ultradeformable liposomes and lipid nanoparticles, offering various advantages, either for dermal and transdermal delivery. However, choosing and designing the most suitable formulation system for a given compound is a complex process. In this chapter, various aspects of formulation-related transdermal drug delivery are discussed and an alternative approach to the design of formulation systems is reviewed. In addition, current formulation-based strategies and the effects of commonly added ingredients for stability and aesthetic purposes are covered. Finally, formulations based on some novel delivery systems are discussed