2 research outputs found
4āAmino-7,8-dihydro-1,6-naphthyridin-5(6<i>H</i>)āones as Inhaled Phosphodiesterase Type 4 (PDE4) Inhibitors: Structural Biology and StructureāActivity Relationships
Rational
design of a novel template of naphthyridinones rapidly led to PDE4
inhibitors with subnanomolar enzymatic potencies. X-ray crystallography
confirmed the binding mode of this novel template. We achieved compounds
with double-digit picomolar enzymatic potencies through further structure-based
design by targeting both the PDE4 enzyme metal-binding pocket and
occupying the solvent-filled pocket. A strategy for lung retention
and long duration of action based on low aqueous solubility was followed. <i>In vivo</i> efficacies were measured in a rat lung neutrophilia
model by suspension microspray and dry powder administration. Suspension
microspray of potent compounds showed <i>in vivo</i> efficacy
with a clear doseāresponse. Despite sustained lung levels,
dry powder administration performed much less well and without proper
doseāresponse, highlighting clear differences between the two
formulations. This indicates a deficiency in the low aqueous solubility
strategy for long duration lung efficacy