(a)
(b)
(c)
(d)
Figure 6: (a) Contour plot for response (drug release at 12 hr) (for   and  ). (b) 3D surface plot of response (drug release at 12 hr) (for   and  ). (c) Contour plot for response (drug release at 12 hr) (for   and  ). (d) 3D surface plot of response (drug release at 12 hr) (for   and  ).