Cefprozil-d4 is the deuterium labeled Cefprozi. Cefprozil is a second-generation cephalosporin type antibiotic. Cefprozil exhibits broad-spectrum antibacterial activity, and is orally active. Cefprozil can be used for the study of pharyngitis, tonsillitis, otitis media, and uncomplicated skin infections[2][3].