The hyper-Gréco-Latin square experimental design as a formulation ingredient selection tool

Formulations are functional mixtures. As such, each ingredient is present to provide or modify one or more properties or functions for the final product. A dilemma facing the development team is this. For each function, there are usually at least a few and often several possible ingredient choices. Therefore, one of the early tasks in developing a new formulation is to find a particularly good combination of ingredients to start an optimization process. This is usually to be done in the face of an often overwhelming number of possible combinations of the choices. This paper is a survey of the risks one faces when embarking on such a task. It features an industrial example of the use of the Latin-square experimental design to minimize those risks during formulation development. Finally, it describes an expansion of the Latin square to a hyper-Greco-Latin square (HGLS) in which six different ingredients, each having five different choices, can be examined in 25 experiments