Table 2. Antagonist Affinity at H1 Receptor (pA2) and Duration of Action in Vitro.
| compd | pA2 ± SEMa | n | wash-out |
|---|---|---|---|
| Azelastine | 9.7 ± 0.1 | 19 | reference |
| 3a·TFA | 9.6 ± 0.2 | 6 | no difference |
| 3b·TFA | 9.2 ± 0.3 | 2 | slower |
| 3c·TFA | 9.88 ± 0.15 | 8 | slower |
| 3d·TFA | 9.5 ± 0.1 | 13 | slower |
| 3e·TFA | 9.7 ± 0.1 | 14 | slower |
| 3f·HCO2H | 9.3 ± 0.1 | 10 | slower |
| 3g | 9.74 ± 0.09 | 20 | slower |
| 3h·TFA | 9.1 ± 0.1 | 13 | slower |
| 9g·TFA | 10.0 ± 0.3 | 12 | slower |
| 10b·HCl | 9.8 ± 0.2 | 9 | slower |
| 10f·HCl | 9.3 ± 0.1 | 8 | slower |
a
All pA2 values calculated from curve shifts generated after 30 min incubation time at 100 nM antagonist concentration.