Prednisone21-aldehyde is a derivative of the synthetic corticosteroid prednisone that has antiviral activity against influenza virus A-PR8 in embryonated chicken eggs. 22-hydroxyPrednisone is an unstable adduct of prednisone. It has been observed following incubation of prednisone with nornicotine. This product is a mixture of prednisone21-aldehyde and 22-hydroxyprednisone.