Abstract
Twelve species of pyridobenzazoles and pyrimidobenzimidazole were examined as inhibitors of the replication of respiratory syncytial virus (RSV) in HeLa cells. From the pyridobenzazoles studied, 2-benzamido-4-cyano-1-oxo-1H, 5H-pyrido [1, 2-α] benzimidazol emerged as a potent inhibitor of the RSV. Based on its inhibitory effect on the cytopathogenicity of the RSV in HeLa cells, the 50% effective dose was found to be 0.95μg/ml. The cytotoxicity of this compound for HeLa cells was examined by monitoring the incorporation of radiolabeled uridine into cellular RNA. The selectivity index was ca. 30, the same as Virazole.
