title: More potency assay results for generic non-USA lots of piperacillin/tazobactam and initial reports for generic meropenem compounds marketed in the USA.
abstract: An ongoing program of international generic antimicrobial potency assays for piperacillin/tazobactam has been summarized here through December 2010, and the initial results for meropenem generic lots from the United States are also presented. Fifteen additional piperacillin/tazobactam generic lots revealed an average of -10% activity (range, +3 to -23%) compared to the branded product (Zosyn®; Wyeth-Pfizer), a finding consistent with prior reports (46 lots) of -16%. In contrast, meropenem branded and generic products had equivalent assay results (5 generic lots from 2 manufacturers [Hospira and Sandoz]). In conclusion, potencies for generic lots of parenteral broad-spectrum β-lactams can vary widely when directly compared to branded products, requiring documentation by chemical, in vitro activity (potency assays as measured here), and purity testing before considering their addition to a hospital formulary.
authors.affiliation: JMI Laboratories, North Liberty, IA, USA. ronald-jones@jmilabs.com
authors.forename: Ronald N
authors.initials: RN
authors.lastname: Jones
authors.forename: Helio S
authors.initials: HS
authors.lastname: Sader
authors.forename: Robert K
authors.initials: RK
authors.lastname: Flamm
authors.forename: Amy A
authors.initials: AA
authors.lastname: Watters
mesh_terms: D000900:Anti-Bacterial Agents / Q000032:analysis / Q000494:pharmacology*; D016568:Drugs, Generic / Q000032:analysis / Q000494:pharmacology*; D016972:Enterobacter cloacae / Q000187:drug effects; D000077731:Meropenem; D008826:Microbial Sensitivity Tests; D010397:Penicillanic Acid / Q000031:analogs & derivatives* / Q000032:analysis / Q000494:pharmacology; D010878:Piperacillin / Q000032:analysis / Q000494:pharmacology; D000077725:Piperacillin, Tazobactam Drug Combination; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D013211:Staphylococcus aureus / Q000187:drug effects; D013845:Thienamycins / Q000032:analysis / Q000494:pharmacology*; D014481:United States
chemical_list: D000900:Anti-Bacterial Agents; D016568:Drugs, Generic; D013845:Thienamycins; D000077725:Piperacillin, Tazobactam Drug Combination; D010397:Penicillanic Acid; D000077731:Meropenem; D010878:Piperacillin