Piperacillin sodium is a new beta-lactam antibiotic developed in 1977 by Ueo et al. at Toyama Chemical Company Ltd of Japan. It is licensed and marketed by Lederle Laboratories as Pipracil in the United States. The chemical name of piperacillin sodium is sodium [2S-[2α, 5α, 6β(S*)]]-6-[[[[(4-ethyl-2,3-dioxo1 -piperazinyl) carbonyll-amino] phenylacetyl] amino] -3,3-dimethyl-7-oxo-4-thia- 1 -azabicyclo[3.2.0]heptane-2-carboxylate. It was originally referred to as T1220. Piperacillin is an acylampicillin derivative and is similar in many respects to the previously marketed carboxypenicillins carbenicillin and ticarcillin, the two new ureidopenicillins mezlocillin and azlocillin, and the third-generation cephalosporin (-like) agents cefotaxime, moxalactam, and cefoperazone (the latter is not yet marketed and is structurally similar to piperacillin)[1].