| Mathematic model | r2 values | ||
| Starch + PLA + B8 1% rif. 10 mg | Starch + PLA + B8 1% rif 10 mg (physical mixture) | Starch + PLA + B8 1% 100 mg de rif. | |
| Zero order | 0.85 | 0.97 | 0.75 |
| Higuchi | 0.89 | 0.88 | 0.94 |
| First order | 0.85 | 0.96 | 0.77 |
| Hixon-Crowell | 0.85 | 0.95 | 0.76 |
| Baker-Lonsdale | 0.95 | 0.92 | 0.98 |