Table 1 Independent variables and levels of experimental design
S.No. | Independent variables | Code level | ||
|---|---|---|---|---|
Low (− 1) | Mid (0) | High (+ 1) | ||
1. | A = polymer (HPMC K15M: ERL100) ratio | 1:1 | 2:1 | 3:1 |
2. | B = concentration of di-butyl phthalate (% w/w) | 20 | 30 | 40 |
3. | C = concentration of d-limonene (% w/w) | 2.5 | 05 | 7.5 |