Table 1: Independent and dependent variables levels in Box-Behnken design.

Levels
−101

Independent variables
= polymer concentration (w/v)103560
= surfactant concentration (w/v)28.5015
= aqueous/organic phase ratio (v/v)2610
= drug concentration (w/v)135

Dependent Variables:Constraints
= -average (d·nm)Minimize
= % drug entrapmentMaximize