Cilomilast(SB 207499; Ariflo) is a potent PDE4 inhibitor with IC50 of about 110 nM, has anti-inflammatory activity and low central nervous system activity. IC50 value: 110 nM Target: PDE 4 Cilomilast (SB-207499) inhibits HPDE4 and LPDE4 catalytic activity with equal potency (Ki ≈100 nM). SB-207499 and rolipram are equipotent against LPDE4, but Cilomilast (Ariflo, SB-207499) is 100-fold less potent against HPDE4. This profile suggests that Cilomilast (Ariflo, SB-207499) retain the anti-inflammatory activity of rolipram yet have a decreased tendency to produce side effects.