Toxic effects of 10 antiviral substances [9-(2-hydroxyethoxymethyl)-guanine (ACV), E-5-(2-bromo vinyl)-2'-deoxyuridine (BVDU), 5-(2-chloroethyl)-2'-deoxyuridine (CEDU), 9-(1,3-dihydroxy-2-propoxymethyl) guanine (DHPG), (S)-9-(3-hydroxy-2-phosphonylmethoxypropyl) adenine (HPMPA), (S)-1-(3-hydroxy-2-phosphonylmethoxypropyl) cytosine (HPMPC), 5'-iodo-2'-deoxyuridine (IDU), phosphonoformic acid (PFA), 9-(2-phosphonylmethoxyethyl) adenine (P MEA) and 5-trifluoromethyl-2'-deoxyuridine (TFT)I on uninfected human corneal cells were evaluated in two experimental models (undisturbed adherence and growth, and wound closure) under continuous drug exposure. The antiviral drugs were ranked in order of toxicity in each of the tests. The influence on toxicity of different experimental parameters such as initial cell density, length of exposure and trauma, was evaluated. There was significant interaction between toxicity and length of exposure. In undisturbed cultures antiviral compounds ranked as follows: PMEA less than or equal to DHPG less than or equal to ACV less than or equal to CEDU < PFA less than or equal to IDU less than or equal to BVDU much less than HPMPC < TFT < HPMPA. Wounding or migration increased the apparent toxicity of the antiviral substances; trauma did not have an additional effect. In conditions where corneal epithelium is poorly populated and ulcerated, wound healing can be delayed by antiviral medication.
