Table 1.

Experimental mixture design (independent variables and selected responses).

Independent factors (% w/w)	Levels
	−1 (Low)	+1 (High)
A – HPC	0	94
B – PEO	0	94
C – PEG 4000	0	3
D – Sorbitol	0	6
Dependent factors (%)
R1 – release at 0.5 h	R2 – release at 6 h