title: Stability of a second-generation cephalosporin veterinary mastitis formulation after electron beam irradiation.
abstract: This study focused on the chemical stability of the cephalosporin (6R, 7R)-7-(1-pentafluorophenoxyacetamido)-3-[2-(5-methyl-1,3,4-thiodiazolyl)thiomethyl]-Delta(3)-cephem-4-carboxylic acid, sodium salt (cephem 1) formulation after electron beam (e-beam) irradiation. The cephem 1 concentrations of samples irradiated at 5, 10, and 15 kilograys for glass vials and low-density polyethylene (LDPE) cannula syringes were not statistically different from the concentrations of the nonirradiated control samples. Samples from each irradiation dose stored in controlled-temperature chambers at 5 degrees C and 30 degrees C for 24 months did not show any concentration changes within statistical limits compared with the nontreated samples. Samples from each irradiation dose stored at 40 degrees C for 12 months also did not show any concentration changes within statistical limits compared with the nontreated samples. The percentage of related substances increased slightly with the increase in e-beam irradiation level and storage temperature, but this increase was within the proposed label claim of 90% to 110% (45-55 mg/g). In conclusion, e-beam sterilization did not affect the chemical stability of cephem 1 intramammary formulation in LDPE cannula syringes, suggesting that e-beam irradiation may be a feasible method for terminal sterilization of this cephem 1 formulation.
authors.affiliation: Chemical and Biopharmaceutical Research, Elanco Animal Health, A Division of Eli Lilly and Company; Greenfield, IN 46140-0708, USA. PJJohns@lilly.com
authors.forename: P J
authors.initials: PJ
authors.lastname: Johns
authors.forename: M
authors.initials: M
authors.lastname: Turberg
authors.forename: K
authors.initials: K
authors.lastname: Willard
authors.forename: D
authors.initials: D
authors.lastname: Matagne
authors.forename: D
authors.initials: D
authors.lastname: Cheesman
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000032:analysis / Q000737:chemistry / Q000528:radiation effects*; D002417:Cattle; D002511:Cephalosporins / Q000032:analysis / Q000737:chemistry / Q000528:radiation effects*; D004355:Drug Stability; D005260:Female; D008414:Mastitis, Bovine / Q000188:drug therapy; D013242:Sterilization; D005464:Fluorobenzenes; D005466:Fluorocarbons
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; C483605:7-(1-pentafluorophenoxyacetamido)-3-(2-(5-methyl-1,3,4-thiodiazolyl)thiomethyl)-delta(3)-cephem-4-carboxylic acid; D005464:Fluorobenzenes; D005466:Fluorocarbons