(a)
(b)
(c)
(d)
Figure 4: (a) Contour plot for response (drug release at 1 hr) (for   and  ). (b) 3D surface plot of response (drug release at 1 hr) (for   and  ). (c) Contour plot for response (drug release at 1 hr) (for   and  ). (d) 3D surface plot of response (drug release at 1 hr) (for   and  ).