title: Amphotericin B delivery from bone cement increases with porosity but strength decreases.
abstract: BACKGROUND
  Amphotericin B is a highly hydrophobic antifungal used for orthopaedic infections. There is disagreement about whether amphotericin B is released when it is loaded in polymethylmethacrylate (PMMA). It is unknown how much a poragen will increase amphotericin B release or decrease the compressive strength of the PMMA.
  
  
  OBJECTIVE
  We therefore measured amphotericin B release and the compressive strength of amphotericin B loaded bone cement with and without adding high-dose poragen.
  
  
  METHODS
  Antifungal-loaded bone cement was formulated with Simplex P cement and 200 mg amphotericin B with and without 10 g cefazolin (poragen) per batch. Twenty standardized test cylinders were eluted in deionized water for each formulation. Cumulative amphotericin B mass and compressive strength were measured. Data were analyzed using repeated-measures analysis of variance.
  
  
  RESULTS
  Antifungal-loaded bone cement (ALBC) with 10 g poragen delivered more amphotericin B than ALBC containing amphotericin B alone by Day 15, 12.76 μg/cylinder (0.5%) versus 1.74 μg/cylinder (0.04%), respectively. With amphotericin B alone, compressive strength was unchanged and compressive strength did not decrease during elution. Adding 10 g poragen to ALBC with 200 mg amphotericin B decreased the compressive strength and compressive strength decreased further during elution, 80, 61, and 46 MPa at 0, 1, and 30 days, respectively.
  
  
  CONCLUSIONS
  Amphotericin B is released in very small amounts from antifungal-loaded bone cement. Release can be increased by adding high-dose poragen, but compressive strength decreases sufficiently to limit its use for implant fixation.
authors.affiliation: Banner Orthopaedic Residency, 901 E Wiletta, Phoenix, AZ 85006, USA.
authors.forename: Chris
authors.initials: C
authors.lastname: Kweon
authors.forename: Alex C
authors.initials: AC
authors.lastname: McLaren
authors.forename: Christine
authors.initials: C
authors.lastname: Leon
authors.forename: Ryan
authors.initials: R
authors.lastname: McLemore
mesh_terms: D000666:Amphotericin B / Q000737:chemistry*; D000935:Antifungal Agents / Q000737:chemistry*; D001843:Bone Cements / Q000737:chemistry*; D002437:Cefazolin / Q000737:chemistry; D019245:Compressive Strength; D016503:Drug Delivery Systems; D019544:Equipment Failure Analysis; D006801:Humans; D007700:Kinetics; D019904:Polymethyl Methacrylate / Q000737:chemistry; D016062:Porosity; D016459:Prosthesis-Related Infections / Q000517:prevention & control
chemical_list: D000935:Antifungal Agents; D001843:Bone Cements; D000666:Amphotericin B; D019904:Polymethyl Methacrylate; D002437:Cefazolin