Drug Information for PIPRACIL (piperacillin for injection) For Intravenous and Intramuscular Use (Wyeth Pharmaceuticals, Inc.): DESCRIPTION

PIPRACIL, sterile piperacillin sodium, is a semisynthetic broad-spectrum penicillin for parenteral use derived from D(-)-α-aminobenzylpenicillin. The chemical name of piperacillin sodium is sodium (2S,5R,6R)-6-[(R)-2-(4-ethyl-2,3-dioxo-1-piperazinecarboxamido)-2-phenylacetamido]-3,-3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate. The chemical formula is C₂₃H₂₆N₅NaO₇S, and the molecular weight is 539.54. Its structural formula is:

Piperacillin sodium powder is a white to off-white solid having the characteristic appearance of products prepared by freeze-drying. It is freely soluble in water and in alcohol. The pH of an aqueous solution containing 400 milligrams per milliliter ranges from 5.5 to 7.5. One g contains 1.85 mEq (42.5 mg) of sodium (Na⁺).