Zosyn(®) (piperacillin/tazobactam) reformulation: Expanded compatibility and coadministration with lactated Ringer’s solutions and selected aminoglycosides

Zosyn(®) , also known as Tazocin(®) for injection, contains piperacillin and tazobactam and was approved by the US Food and Drug Administration in 1993 for the treatment of indicated serious infections. In 1995, United States Pharmacopoeia and European Pharmacopoeias reduced the particulate limit for injectables by 40%, based on general safety concerns. Wyeth attempted to control sporadic batch failures (associated with increased particulate formation) by shortening product expiration dating from 36 to 24 months and optimizing the stopper siliconization process. These modifications did not correct the problem completely. Wyeth reformulated Zosyn by incorporating two stabilizing functional excipients, ethylene diamine tetraacetic acid disodium salt (EDTA disodium) and sodium citrate, which solved the particulate formation problem. These two functional excipients also allowed for the first time Y-site coadministration of reformulated Zosyn product with amikacin and gentamicin at specific doses and concentrations, and with certain diluents, and the use of Ca(++) ion-containing Lactated Ringer’s for admixture preparation. Reformulated Zosyn (approved 2005) may provide useful options of drug administration to healthcare professionals to lessen levels of particulates. Supportive data is provided for the expanded compatibility of reformulated Zosyn with different types of Ringer’s solutions used globally and for the Y-site coadministration of amikacin and gentamicin aminoglycosides.