[Antiviral effect of (S)-1-(3-hydroxy-2-phosphonylmethoxypropyl) cytosine on adenovirus].

PURPOSE: Adenovirus is the most frequent causative virus of conjunctivitis in Japan. Recently (S)-1-(3-hydroxy-2-phosphonylmethoxypropyl) cytosine (HPMPC) has been promoted as a new drug against adenoviral conjunctivitis. So we examined the antiviral activity of HPMPC against adenoviruses in vitro. METHOD: The antiviral activity of HPMPC against adenovirus (Ad) type 3, type 4, type 19, and type 37 isolated from conjunctivial scrapings in Japan and the prototype of adenovirus type 5 was examined by plaque reduction assay using A 549 cells in vitro. RESULTS: The 50% inhibitory dose (ID50) of HP-MPC was 3.50 (1.44-4.79) micrograms/ml for Ad type 3, 4.50 (4.17-4.92) micrograms/ml for Ad type 4, 2.11 (1.03-3.13) micrograms/ml for Ad type 5, 1.64 (1.40-2.02) micrograms/ml for Ad type 19, and 2.02 (1.17-2.73) micrograms/ml for type 37. The 50% cytotoxic dose of HPMPC for A 549 cells was 205 micrograms/ml by the deoxythimidine uptake inhibition test, and 537 micrograms/ml by the trypan blue exclusion inhibition test. CONCLUSIONS: HPMPC proved to be highly effective in inhibiting replication of adenoviruses at lower concentrations than the cytotoxic level in vitro.