Table 3. pI50 and IC50 values for ibuprofen, flurbiprofen and their metabolites towards the inhibition of 0.5 µM [3H]AEA hydrolysis by rat brain FAAH.
| pI50 (IC50, µM) | ||
| Compound | pH 6.0 | pH 7.3 |
| Ibuprofen | 4.15±0.05 (70 µM) | 3.59±0.05 (260 µM) |
| 1′-OH-Ibuprofen | 3.47±0.07 (340 µM) | 47±0.8% inhibition @ 1000 µM |
| 2′-OH-Ibuprofen | 3.42±0.06 (380 µM) | 15±7% inhibition @ 1000 µM |
| 3′-OH-Ibuprofen | 3.70±0.03 (200 µM) | 3.01±0.04 (990 µM) |
| Carboxyibuprofen | 3.38±0.08 (410 µM) | 31±4% inhibition @ 1000 µM |
| Flurbiprofen | 4.56±0.05 (28 µM) | 4.29±0.04 (51 µM) |
| 4′-OH-Flurbiprofen | 4.07±0.05 (84 µM) | 3.50±0.03 (310 µM) |
Values were determined using the log(inhibitor) vs. response – variable slope (four parameters) algorithm in the Prism 6 computer programe, with top and bottom values constrained to 100% and 0%, respectively. In all cases, Akaike’s informative criteria indicated that the curves were better fitted to these constraints than the equivalent algorithm where the bottom value was not constrained.