title: Evaluation of in vitro serial antibiotic elution from meropenem-impregnated polymethylmethacrylate beads after ethylene oxide gas and autoclave sterilization.
abstract: OBJECTIVE
  To determine the elution properties of meropenem and to compare the elutions of meropenem-impregnated polymethylmethacrylate (PMMA) beads without sterilization (P-M-C) to those sterilized with steam (P-M-A) and ethylene oxide gas (P-M-EO).
  
  
  METHODS
  A commercial bead mould was used to produce four groups of beads: one group without antibiotic (negative control), and three groups of meropenem-impregnated beads: P-M-C, P-M-A, and P-M-EO. The beads were placed in a phosphate buffered solution and eluent samples were collected. Concentrations of the antibiotic in eluent samples from the two sterilized groups and the control beads were determined using a microbiological assay at 1, 3, 6 and 12 hours and at 1, 2, 3, 6, 9, 12, 15, 18, 22, 26, and 30 days.
  
  
  RESULTS
  The microbiological assay resulted in no zone of inhibition at all time periods for the P-M-A samples and the samples of PMMA without antimicrobial. The meropenem concentration on the eluent remained above 4 mcg/ml for 15 days in the P-M-C group and until day 18 for P-M-EO group. There was no statistical difference in AUC0-∞ (p<0.318), however significance did occur for MRT (p<0.005) when comparing P-M-C and P-M-EO with the later being higher.
  
  
  CONCLUSIONS
  The meropenem incorporated in the PMMA beads eluted effectively and gradually decreased after the 24 hour peak, but remained above the concentration level of 4 mcg/ml for 15 days in the P-M-C group and until day 18 for P-M-EO group. Ethylene oxide does not adversely affect meropenem's elution from PMMA beads.
authors.affiliation: College of Veterinary Medicine, Mississippi State University, Clinical Sciences, Small Animal Surgery, 240 Wise Center, Mississippi State, Starkville, MS 39769, United States. baez@cvm.msstate.edu
authors.forename: L A
authors.initials: LA
authors.lastname: Báez
authors.forename: C
authors.initials: C
authors.lastname: Langston
authors.forename: S
authors.initials: S
authors.lastname: Givaruangsawat
authors.forename: R
authors.initials: R
authors.lastname: McLaughlin
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry*; D005027:Ethylene Oxide / Q000737:chemistry*; D006358:Hot Temperature; D000077731:Meropenem; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D013242:Sterilization / Q000379:methods*; D013845:Thienamycins / Q000737:chemistry*; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D013845:Thienamycins; D019904:Polymethyl Methacrylate; D000077731:Meropenem; D005027:Ethylene Oxide