The effect of certain mannich N-bases, derivatives of isatin beta-thiosemicarbazone, on the replication of vaccinia virus in in vitro studies.

Twenty-three Mannich mono- and bis-N-bases, derivatives of isatin beta-thiosemicarbazone (IBT), were synthetized. Eighteen of these were tested for their inhibitory effect on the replication of vaccinia virus (IHD strain) in cultures of chick embryo fibroblasts. All the compounds studied showed antiviral activity, demonstrated by the agar-diffusion method (screening). The concentrations that reduced the number of viral plaques to 50% (PRD50) and the values of the therapeutic index (Th.i.) of the compounds tested were determined by the methyl-cellulose technique. The results obtained permitted analysis of their pharmaceutical effect relative to the chemical structure of the molecule, under the described experimental conditions.