Thymine arabinoside (Ara-T) topical and iontophoretic application for herpes simplex virus type 1 and type 2 skin infections in hairless mice.

The antiviral agent thymine arabinoside (9-beta-D-arabinofuranosyl thymine, Ara-T) was applied topically and by anodal (+) iontophoresis in a NaCl solution to Herpes simplex virus type 1 (HSV-1), and Herpes simplex virus type 2 (HSV-2) skin infections in hairless mice. The chemotherapeutic efficacy of Ara-T was evaluated employing the parameters of mean lesion score, number of mice with signs of neurological involvement (paralysis), mortality and mean survival time. Anodal (+) iontophoresis of 0.4% Ara-T in a 0.1 M NaCl solution significantly suppressed HSV-1 skin infection, but the infection was not altered by topical application of 3% Ara-T. HSV-2 infection was refractory to both topical and iontophoretic application of Ara-T. This is the first report of the in vivo efficacy of Ara-T for HSV-1 skin infections.