Shape of the scoring function, the value of which (the score) gives merit to gel spreading performance [10]. In this model, the score is a function of predicted coated area A. Amax is the target coated area, which is the surface area of the vagina. A* is a limiting predicted value of A, which is equal to Amax/[1−VL/V] where V is gel volume, and VL is an upper limit on leaked volume. That is, VL is a maximal value of V at which the value of the score drops to zero. This is set by the user of the model