ANTIVIRAL ACTIVITY OF FA-11H ON THE INFECTIVITY AND REPLICATION OF HERPES-SIMPLEX VIRUS TYPE-1 IN CULTURED-CELLS

The highest concentration lacking cytotoxicity (h.c.l.c.) of the acid FA-11H, related to ester FA-11 (ethyl inuoromethyl-2-methylthio-5-pyri midinecarboxylate) was determined on Vero cultured cells. At this conc entration (300 mu g/ml) FA-11H produced an 81.4% inhibition of herpes simplex virus type 1 infectivity with respect to the plaque formation detected in control infected cultures. This inhibitory activity was su bstantiated by studies on progeny production. FA-11H revealed a higher therapeutic index than that of the related ester FA-11. However, the therapeutic index of FA 11H appeared to be lower than that of its pota ssium salt. These results indicate that the presence of potassium ions could facilitate the internalization and therefore the antiviral acti vity of the anions corresponding to analysed compound.