Anti-trachoma Activity of Rifampicin and Rifamycin SV Derivatives

Abstract

RIFAMPICIN effectively inhibits the replication of trachoma agents both in infected cell cultures in vitro¹ and in embryonated eggs in vivo². It acts during the initial developmental stages, characterized by active RNA synthesis³. The anti-trachoma inhibitory effect of rifampicin exceeded that of rifamycin SV^1,2, indicating that the presence of a hydrazone sidechain in carbon 3 of the chromophoric part of rifamycin SV might be concerned in the activity. To determine the function of the side chain, we have compared the effect of four compounds synthesized by adding to the formyl-rifamycin derivative of rifamycin SV different side chains at carbon 3. We have found that the presence of a hydrazone side chain in the rifamycin SV molecule enhanced the anti-trachoma activity of the drug in vitro and was essential for the inhibition of trachoma agent in vivo.