Table 2. Matrix-corrected apparent EPI-equivalent concentrations in BSA-free and BSA-containing formulations following exposure to increasing PET MNP levels. EPI-equivalent responses were estimated from absorbance at 480 nm using the corresponding matrix controls. Values are presented as mean ± SD from three independently prepared samples (n = 3). The percentage response relative to the nominal EPI concentration is shown in parentheses. Negative values following matrix-control subtraction indicate responses close to the analytical baseline and do not represent negative EPI concentrations.
| Sample | EPI1 (1 µM) | EPI2 (10 µM) | EPI3 (100 µM) |
|---|---|---|---|
| EPI | 0.71 ± 0.15 (71.1%) | 9.32 ± 0.70 (93.2%) | 106.47 ± 1.24 (106.5%) |
| EPI + MNP1 | 0.42 ± 0.01 (42.4%) | 5.67 ± 0.20 (56.7%) | 56.36 ± 0.05 (56.4%) |
| EPI + MNP2 | 0.19 ± 0.32 (19.2%) | 3.62 ± 0.42 (36.2%) | 49.76 ± 0.75 (49.8%) |
| EPI + MNP3 | 0.03 ± 0.59 (3.2%) | 2.32 ± 0.38 (23.2%) | 43.17 ± 0.57 (43.2%) |
| BSA + EPI | 0.01 ± 0.01 (0.8%) | 3.38 ± 0.31 (33.8%) | 43.06 ± 2.12 (43.1%) |
| BSA + EPI + MNP1 | −0.04 ± 0.19 (−4.0%) | 3.58 ± 0.27 (35.8%) | 43.67 ± 2.22 (43.7%) |
| BSA + EPI + MNP2 | 0.93 ± 0.02 (92.6%) | 3.75 ± 0.71 (37.5%) | 41.13 ± 4.86 (41.1%) |
| BSA + EPI + MNP3 | 0.35 ± 0.09 (35.2%) | 3.43 ± 0.37 (34.3%) | 41.40 ± 1.58 (41.4%) |