SPL Set ID: f41d8abd-7792-4918-1b93-bd83ea01955e

PRIMAXIN (imipenem and cilastatin) for Injection is a sterile formulation of imipenem, a penem antibacterial, and cilastatin, a renal dehydropeptidase inhibitor with sodium bicarbonate added as a buffer. PRIMAXIN is an antibacterial drug for intravenous administration. Imipenem (N-formimidoylthienamycin monohydrate) is a crystalline derivative of thienamycin, which is produced by Streptomyces cattleya . Its chemical name is (5 R ,6 S )-3-[[2-(formimidoylamino)ethyl]thio]-6-[( R )-1-hydroxyethyl]-7-oxo-1-azabicyclo[3.2.0]hept-2-ene-2-carboxylic acid monohydrate. It is an off-white, nonhygroscopic crystalline compound with a molecular weight of 317.37. It is sparingly soluble in water and slightly soluble in methanol. Its empirical formula is C 12 H 17 N 3 O 4 S∙H 2 O, and its structural formula is: Cilastatin sodium is the sodium salt of a derivatized heptenoic acid. Its chemical name is sodium ( Z )-7[[( R )-2-amino-2-carboxyethyl]thio]-2-[( S )-2,2-dimethylcyclopropanecarboxamido]-2-heptenoate. It is an off-white to yellowish-white, hygroscopic, amorphous compound with a molecular weight of 380.43. It is very soluble in water and in methanol. Its empirical formula is C 16 H 25 N 2 O 5 SNa, and its structural formula is: Each single-dose vial of PRIMAXIN contains 500 mg imipenem (equivalent to 530 mg imipenem monohydrate), 500 mg cilastatin (equivalent to 531 mg cilastatin sodium), and 20 mg sodium bicarbonate (used as a buffer). PRIMAXIN is buffered to provide solutions in the pH range of 6.5 to 8.5. There is no significant change in pH when solutions are prepared and used as directed [see How Supplied/Storage and Handling (16.1) ]. PRIMAXIN 500 contains 37.5 mg of sodium (1.6 mEq). Solutions of PRIMAXIN range from colorless to yellow. Variations of color within this range do not affect the potency of the product. Chemical Structure Chemical Structure