What is the fine-grained topic of the following text: Response surface plot, contour plot, overlaid contour plot and response optimizer plot were drawn and an optimum formulation was selected as CCD F8 which contains 40 mg (20 %) of β-cyclodextrin and 11.24 mg (5.62 %) of Crospovidone. Only return the topic.
Optimization of Formulation Using Response Surface Plots and Contour Plots