Cell experiment:

Blood from anesthetized rats is collected in heparin tubes, immediately distributed in 96-well microplates (250 μL/well) and incubated for 30 min at 37℃/5% CO2. Twenty-five microliters of vehicle or increasing concentrations of CI-1044, rolipram, cilomilast or solvant (saline/DMSO<0.1%) are added in wells and incubated for 30 min before the addition of LPS (100 μg/mL) or saline. Plasma is removed after a 22 to 24 h incubation at 37℃/5% CO2, transferred in another 96-well microplate and stored at ) -80℃ until a TNF-α assay by ELISA[1].

Animal experiment:

Male rats (200 to 220 g) are used and receive either vehicle or CI-1044 orally at 0.4, 1, 4, 10 and 40 mg/kg. In the single administration experiment, all treatments are given 1 h before blood collection. In the repeated administration experiment, the treatments are given twice a day during 13 days and once on day 14, 1 h before blood sampling[1].

CI-1044 is an orally active PDE4 inhibitor with IC50s of 0.29, 0.08, 0.56, 0.09 μM for PDE4A5, PDE4B2, PDE4C2 and PDE4D3, respectively.

CI-1044 is an orally active PDE4 inhibitor with IC50s of 0.29, 0.08, 0.56, 0.09 μM for PDE4A5, PDE4B2, PDE4C2 and PDE4D3, respectively. CI-1044 selectively inhibits PDE4 crude extract from U937 cells with an IC50 value of 0.27±0.02 μM being threefold more potent than rolipram (IC50=0.91±0.14) and tenfold less potent than cilomilast (IC50=0.026±0.007) in the same assay. In the presence of PDE4 inhibitors, the production of TNF-α is dose dependently decreased with mean IC50 values from three separate experiments of 0.31±0.05, 0.26±0.05 and 0.11±0.01 μM, for CI-1044, cilomilast and rolipram, respectively[1].

TNF-α production is dose-dependently inhibited by CI-1044, rolipram and cilomilast with ID50s of 0.4, 1.4 and 1.6 mg/kg respectively following single oral administration. Following repeated administration with CI-1044, the ID50 value represents 0.5 mg/kg p.o.. CI-1044 plasma levels increase proportionally with doses ranging between 0.1 and 40 mg/kg p.o. (R2=0.878). CI-1044 dose dependently inhibits the accumulation of eosinophils in Bronchoalveolar lavages (BAL) fluids with an ID50 value of 3.25 mg/kg. A single dose treatment with CI-1044 (10 mg/kg, p.o.) 24, 8, 3 or 1 h before the antigen challenge induces 6, 56, 48 and 79% inhibition in the number of eosinophils in BAL[1].

[1]. Pruniaux MP, et al. Relationship between phosphodiesterase type 4 inhibition and anti-inflammatory activity of CI-1044 in rat airways. Fundam Clin Pharmacol. 2010 Feb;24(1):73-82.