Antagonist potency estimates (−logKB values) for indole CRTH2 antagonists determined from radioligand binding assays Values are the mean of three to five independent experiments performed in duplicate. Unpaired t tests showed that TM30643 and TM30089 had significantly higher affinity to the receptor than ramatroban and 30642, respectively (p < 0.01) in both radioligand binding assays.
| Assay | ||
|---|---|---|
| Compound | [3H]PGD2 Inhibition Binding | [3H]PGD2 Homologous Competition Binding |
| Ramatroban | 8.19 ± 0.06a | 8.13 ± 0.01b |
| TM30642 | 8.15 ± 0.07a | 8.35 ± 0.03b |
| TM30643 | 8.85 ± 0.06a | 8.89 ± 0.04c |
| TM30089 | 8.74 ± 0.09a | 8.93 ± 0.05c |
↵ a Parameter estimates represent the negative logarithm of the antagonist dissociation constant, derived by nonlinear regression analysis according to a competitive model (eq. 2).
↵ b Negative logarithm of the antagonist dissociation constant, derived by global nonlinear regression analysis according to a competitive binding model (eq. 4).
↵ c Negative logarithm of the antagonist dissociation constant, derived by global nonlinear regression analysis according to a noncompetitive binding model (eq. 5).