Vilanterol trifenatate

Kinase experiment:

Saturation, association, and dissociation binding studies are performed for [3H]Vilanterol to determine receptor binding kinetics at the β2-AR (equilibrium dissociation constant (KD), total number of receptors (Bmax), association rate (kon), and dissociation rate (koff) are calculated). For saturation binding, membranes (in a volume of 1.4 mL to avoid ligand depletion) are incubated with increasing concentrations of [3H]Vilanterol (~0.01-1.3 nM) for 5 h before filtration. For association binding, membranes are incubated with different concentrations of [3H]Vilanterol (~0.1-1.9 nM) for varying incubation times up to 1 h before filtration. For dissociation binding, membranes are preincubated for 1 h with a fixed concentration of [3H]Vilanterol (~1.1 nM) before dissociation is initiated by a 1:20 dilution in binding buffer (containing 10 μM cold Vilanterol) and then incubated for varying times up to 8 h before filtration. Saturation binding is also completed for [3H]CGP12177 (increasing concentrations of ~0.01-2.8 nM) in the same format as described above for [3H]Vilanterol. To determine the affinity of β2-AR agonists and antagonists, competition binding displacement studies are completed in which membranes are incubated with a fixed concentration of [3H]Vilanterol (~0.2 nM) and increasing concentrations of unlabeled agonist/antagonist for 5 h before filtration. All competition binding displacement studies are completed in the presence of 100 µM Gpp(NH)p to ensure that binding curves are monophasic[1].

References:

[1]. Slack RJ, et al. In vitro pharmacological characterization of vilanterol, a novel long-acting β2-adrenoceptor agonist with 24-hour duration of action. J Pharmacol Exp Ther. 2013 Jan;344(1):218-30
[2]. Kempsford R, et al. Vilanterol trifenatate, a novel inhaled long-acting beta2 adrenoceptor agonist, is well tolerated in healthy subjects and demonstrates prolonged bronchodilation in subjects with asthma and COPD. Pulm Pharmacol Ther. 2013 Apr;26(2):256-
[3]. Harrell AW, et al. Metabolism and disposition of Vilanterol, a long-acting β(2)-adrenoceptor agonist for inhalation use in humans. Drug Metab Dispos. 2013 Jan;41(1):89-100.