Table 2.

Box-Behnken Design with 3 Variables and 3 Levels and the Measured Values of Responses

	Independent variable			Dependent variable
Formulation number	Glycolide content (X1;%)	Polymer concentration (X2;% w/v)	Drug-to-polymer ratio (X3)	Burst release (Y1;%)	Drug loading (Y2;% w/w)	Particle size (Y3; μm)
1	0	3	0.15	16.8	10.5	2.4
2	50	9	0.2	18.7	10.35	3.1
3	25	15	0.2	14.65	15	2.4
4	50	9	0.1	19.4	8.7	2.8
5	25	3	0.1	23.6	6.4	1.6
6	25	9	0.15	15.89	11.4	1.8
7	25	9	0.15	15.89	11.4	1.8
8	50	15	0.15	13.8	12.4	3.1
9	25	3	0.2	19.65	6.8	2.4
10	0	9	0.2	16.4	15.1	2.7
11	25	9	0.15	15.89	11.4	1.8
12	0	15	0.15	12.8	11.6	3.7
13	50	3	0.15	24.9	4.5	3.5
14	0	9	0.1	13.8	8.7	3.2
15	25	15	0.1	12.7	9.2	3.6

This design was used to determine the influence of glycolide content, polymer concentration, and drug-to-polymer ratio on particle size, drug loading, and burst release for SAR 1118 microspheres.