Table 1. Combination index (CI) values for TC-1 cells treated with Radachlorin/PDT and As4O6.
| Day 1 | Day 2 | Day 3 | Day 4 | ||||||
| As4O6 | PDT | f*(%) | CI** | f(%) | CI | f(%) | CI | f(%) | CI |
| 3uM | 0.2ug/ml | 17.3 | 1.61 | 9.7 | 1.16 | 8.2 | 0.98 | 8.7 | 0.67 |
| 3uM | 0.15ug/ml | 22.6 | 1.52 | 12.7 | 1.13 | 15.7 | 1.02 | 26.4 | 1.19 |
The combination index (CI) values were calculated using the Chou and Talalay mathematical model for drug interaction on Calcusyn software. A CI was equal to 1 denotes additivity; antagonism if the CI>1; CI values between 1 and 0.7 indicate slight synergism; 0.7 to 0.3, synergism; <0.3, strong synergism. *Viability.