Results – NRU – POLYSOL®PGA
After incubation, the medium is replaced with fresh medium + NR medium, cells are incubated for 3 hrs at 37°C. Then cells are washed more times to eliminate dye wastes. The fluorimeter reading is made at 540 nm wavelength. The results are expressed in terms of viability:
OD540 treated cultures x 100 % Viability = OD540 untreated control cultures
The cytotoxicity data obtained with the NRU assay were according the theoretical IC50 value (Inhibiting Concentration 50), i.e. the concentration of test compound which induce a decrease of cell survival by 50% as compared to untreated cultures. The cytotoxicity results have been corrected subtracting the cytotoxicity due to the diluent medium.
The IC50 value (Inhibiting Concentration 50) is the concentration of test compound which induces a decrease of cell survival by 50% . It makes it possible to evaluate the potential irritating effect as described:
IC50 < 1 mg/ml means a cytotoxic/ irritating effect.
IC50 > 1mg/ml means the absence of cytotoxic / no irritating effect.
| Sample | Cell viability (%) | Media | ||
| Positive control: SDS 0,06 mg/ml | 5,40% | 5,40% | 5,40% | 5,40% |
| Negative control : D-MEM | 100% | 100% | 100% | 100% |
| 20 mg/ml | 100% | 100% | 100% | 100% |
| 10 mg/ml | 100% | 100% | 100% | 100% |
| 5 mg/ml | 100% | 100% | 100% | 100% |
| 2,5 mg/ml | 100% | 100% | 100% | 100% |
| 1,25 mg/ml | 100% | 100% | 100% | 100% |
| 0,625 mg/ml | 100% | 100% | 100% | 100% |
| 0,312 mg ml | 100% | 100% | 100% | 100% |
The IC50 value is calculated on the basis of the cell viability values obtained, in relation to the concentration in mg/ml of the tested product.
An IC50 value> 1mg / ml indicates a product without a potential for irritation;
An IC50 value <1mg / ml indicates a product with a potential for irritation