In vitro virucidal activity by components of a topical film-forming medication.

This study evaluated the in vitro virucidal activity of soluble components of a topical film-forming medication, Zilactin, against Herpes simplex virus type 1 (HSV-1). Using a standard plaque reduction assay, a 1:10 dilution of the experimental liquid resulted in total destruction of infectious HSV-1. The phenomenon could not be explained by ethanol concentration or lowering of pH, both of which had no effect on control samples. As employed in this assay, Zilactin diluted 1:10 did not demonstrate cyctotoxicity to the cell monolayer system. The implications of these findings on the design and implementation of clinical trials are discussed, with special reference made to the restrictions imposed by the natural history of clinical lesions caused by HSV-1.