title: A daptomycin-xylitol-loaded polymethylmethacrylate bone cement: how much xylitol should be used?
abstract: BACKGROUND
  The rate of release of an antibiotic from an antibiotic-loaded polymethylmethacrylate (PMMA) bone cement is low. This may be increased by adding a particulate poragen (eg, xylitol) to the cement powder. However, the appropriate poragen amount is unclear.
  
  
  OBJECTIVE
  We explored the appropriate amount of xylitol to use in a PMMA bone cement loaded with daptomycin and xylitol.
  
  
  METHODS
  We prepared four groups of cement, each comprising the same amount of daptomycin in the powder (1.36 g/40 g dry powder) but different amounts of xylitol (0, 0.7, 1.4, and 2.7 g); the xylitol mass ratio (X) (mass divided by mass of the final dry cement-daptomycin-xylitol mixture) ranged from 0 to 6.13 wt/wt%. Eight mechanical, antibiotic release, and bacterial inhibitory properties were determined using three to 22 specimens or replicates per test. We then used an optimization method to determine an appropriate value of X by (1) identifying the best-fit relationship between the value of each property and X, (2) defining a master objective function incorporating all of the best fits; and (3) determining the value of X at the maximum master objective function.
  
  
  RESULTS
  We found an appropriate xylitol amount to be 4.46 wt/wt% (equivalent to 1.93 g xylitol mixed with 1.36 g daptomycin and 40 g dry cement powder).
  
  
  CONCLUSIONS
  We demonstrated a method that may be used to determine an appropriate xylitol amount for a daptomycin-xylitol-loaded PMMA bone cement. These findings will require in vivo confirmation.
  
  
  CONCLUSIONS
  While we identified an appropriate amount of xylitol in a daptomycin-xylitol-loaded PMMA bone cement as a prophylactic agent in total joint arthroplasties, clinical evaluations are needed to confirm the effectiveness of this cement.
authors.affiliation: Department of Mechanical Engineering, The University of Memphis, 316 Engineering Science Building, Memphis, TN, 38152, USA.
authors.forename: Ali
authors.initials: A
authors.lastname: Salehi
authors.forename: Ashley Cox
authors.initials: AC
authors.lastname: Parker
authors.forename: Gladius
authors.initials: G
authors.lastname: Lewis
authors.forename: Harry S
authors.initials: HS
authors.lastname: Courtney
authors.forename: Warren O
authors.initials: WO
authors.lastname: Haggard
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D001843:Bone Cements / Q000737:chemistry*; D017576:Daptomycin / Q000008:administration & dosage*; D004337:Drug Carriers; D006801:Humans; D014993:Xylitol / Q000008:administration & dosage*
chemical_list: D000900:Anti-Bacterial Agents; D001843:Bone Cements; D004337:Drug Carriers; D017576:Daptomycin; D014993:Xylitol