In vitro potency evaluations of various piperacillin/tazobactam generic products compared with the contemporary branded (Zosyn, Wyeth) formulation.
Twenty-three generic intravenous piperacillin/tazobactam products were compared for in vitro activity to the branded formulation (Zosyn, Wyeth, Philadelphia, PA) by disk diffusion and incremental broth microdilution assay methods. All but 1 lot demonstrated significantly decreased activity (-5 to -35%), necessitating further investigations regarding the chemical purity, potency, and therapeutic equivalence of these products worldwide. The average -16% activity across all generic lots was equivalent to underdosing piperacillin/tazobactam by 2.6 g daily for serious clinical infections (4.5 g Q6 h).
Jones
Ronald N
RN
JMI Laboratories, North Liberty, IA 52317, USA. ronald-jones@jmilabs.com
Fritsche
Thomas R
TR
Moet
Gary J
GJ
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D016568:Drugs, Generic / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D010397:Penicillanic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D010878:Piperacillin / Q000494:pharmacology; D000077725:Piperacillin, Tazobactam Drug Combination
D000900:Anti-Bacterial Agents; D016568:Drugs, Generic; D000077725:Piperacillin, Tazobactam Drug Combination; D010397:Penicillanic Acid; D010878:Piperacillin