Antiinflammatory benzimidazole derivative with inhibitory effects on neutrophil function

Abstract

5-Methyl-2,2,2-trifluoroethylsulfonyl-1H-benzimidazole (BI-L-45 XX) inhibits both neutrophil enzyme release and chemotaxisin vitro and also inhibits chemotaxisin vivo. BI-L-45 XX has an IC₅₀ between 16μM and 25 μM in inhibiting lysosomal enzyme release from human peripheral blood neutrophils. In a Boyden chamber experiment, BI-L-45 XX inhibited migration in response to fMLP with an IC₅₀ of 5 μM. When given orally to passively sensitized rats at doses of 0.1 to 1.0 mg/kg, it inhibited migration of neutrophils to the pleural cavity in response to an antigen (ovalbumin) challenge. BI-L-45 XX also shows activity in the developing adjuvant arthritis model, with an ED₅₀ of 45 mg/kg, while exhibiting no significant inhibition of cyclooxygenase in a human platelet assay. This suggests the possibility that its antiinflammatory activity may be in part mediated by its effect on neutrophil function.