Two processes, the selection of components for assembly into membranes and the optimisation of the membrane formulation, are fundamental to the research, development and application of membrane systems. Many different membrane systems have been developed. However, relatively few of these have been developed commercially. This is partly due to the lack of an effective strategy for the optimisation of membrane formulations towards various industrial applications. This paper deals with a recently developed formulation-optimisation approach to the development of membrane systems. Thus, the experiments are designed rationally to reduce the number of required experimental runs. In this way, the optimal membrane formulation can be acquired efficiently.