Table 1.
Independent and dependent variables of VNP-TPGS-ALA transdermal film formulations in Box–Behnken design
| Independent variables | Unit | Levels
|
||
|---|---|---|---|---|
| −1 | 0 | 1 | ||
|
| ||||
| ALA in TPGS (X1) | % | 0 | 15 | 30 |
| Citral concentration (X2) | % | 1 | 2 | 3 |
| PG concentration (X3) | % | 1 | 3 | 5 |
|
| ||||
| Dependent variables | Unit |
Constraints
|
||
| Low | High | Goal | ||
|
| ||||
| Elongation percent (Y1) | % | 5 | 140 | 72.5 |
| Initial permeation after 2 hours (Y2) | % | 10.24 | 30.36 | 20.3 |
| Cumulative permeation after 24 hours (Y3) | % | 57.72 | 97.29 | 77.5 |
Abbreviations: ALA, alpha lipoic acid; PG, propylene glycol; TPGS, D-α-tocopherol polyethylene glycol 1000 succinate; VNP, vinpocetine.