Table 1.

The coded and actual values of the variables used in central composite design

Symbol	Independent variables	Levels
		− α	− 1	0	1	+ α
A	Water–oil ratio (v/v)	3:1	5:1	7:1	9:1	11:1
B	Polymer content (%)	2	2.5	3	3.5	4
C	PVA content (%)	0.05	0.1	0.15	0.2	0.25
D	Homogenization time (min)	3	5	7	9	11
Constraints	Dependent variables (Units)
Minimize	Y = particle size (nm)

PVA polyvinyl alcohol