Table 4.
Optimal calculated variables and observed, predicted, and residual values for responses
| Independent variables | Optimum | Dependent variables | Predicted | Observed | Residual |
|---|---|---|---|---|---|
| ALA in TPGS (%) | 16.62 | Elongation percent (%) | 72.5 | 75.69 | 3.19 |
| Citral concentration (%) | 3.0 | Initial permeation after 2 hours (%) | 19.98 | 18.89 | 1.09 |
| PG concentration (%) | 2.18 | Cumulative permeation after 24 hours (%) | 78.2 | 74.74 | 3.46 |
Abbreviations: ALA, alpha lipoic acid; PG, propylene glycol; TPGS, D-α-tocopherol polyethylene glycol 1000 succinate.