Stability of 0.5% cidofovir stored under various conditions for up to 6 months.

OBJECTIVE: To evaluate the effect of time, temperature and storage vial material on the antiviral activity of 0.5% cidofovir solution. PROCEDURES: Commercial 7.5% cidofovir solution for injection was diluted with normal saline to a 0.5% concentration. Aliquots were stored in plastic and glass vials at 4, -20, and -80 degrees C for 30, 60, 120, and 180 days. Antiviral activity against feline herpesvirus was evaluated in a virus titration assay at time zero (baseline) and at each subsequent time point. RESULTS: Cidofovir caused a fourfold log reduction in virus titer at baseline and at each time point and for each storage condition (P < 0.001). CONCLUSION: 0.5% cidofovir demonstrated stable antiviral activity when stored for up to 6 months in glass or plastic, at 4, -20, and -80 degrees C.