Biological Activity
apparent ic50 3.2 pm, steady state ic50 < 0.5 pmgsk256066 is an exceptionally high-affinity and selective inhibitor of pde4 designed for inhaled delivery.oral phosphodiesterase (pde) 4 inhibitors have demonstrated clinical efficacy in chronic obstructive pulmonary disease and asthma.
in vitro
gsk256066 is a slow- and tight-binding inhibitor of pde4b, more potent than any previously documented compound, for example roflumilast, tofimilast and cilomilast [1].
in vivo
when administered by the intratracheal route to rats, gsk256066 inhibited lps-induced pulmonary neutrophilia with ed50s of 1.1 μg/kg (aqueous suspension) and 2.9 μg/kg (dry powder formulation) and was more potent than an aqueous suspension of the corticosteroid fluticasone propionate (ed50 9.3 μg/kg) [1].
References
[1] tralau-stewart cj, williamson ra, nials at, gascoigne m, dawson j, hart gj, angell ad, solanke ye, lucas fs, wiseman j, ward p, ranshaw le, knowles rg. gsk256066, an exceptionally high-affinity and selective inhibitor of phosphodiesterase 4 suitable for administration by inhalation: in vitro, kinetic, and in vivo characterization. j pharmacol exp ther. 2011;337(1):145-54.
[2] watz h, mistry sj, lazaar al; ipc101939 investigators. safety and tolerability of the inhaled phosphodiesterase 4 inhibitor gsk256066 in moderate copd. pulm pharmacol ther. 2013;26(5):588-95.