title: Continuous-release or burst-release of the antimicrobial peptide human lactoferrin 1-11 (hLF1-11) from calcium phosphate bone substitutes.
abstract: OBJECTIVE
  In order to identify possible drug delivery systems against resistant bone infection, we determined the release of the antimicrobial peptide (AMP) human lactoferrin 1-11 (hLF1-11) from commercially available bone substitutes.
  
  
  METHODS
  We combined six calcium phosphate cements and six granule-types with 5 mg/g hLF1-11 and measured its availability and release in vitro from cements (7 days) and granules (3 days). The integrity and antimicrobial activity of the hLF1-11 that was released during the first 24 h were measured, using mass spectrometry, and a killing assay on methicillin-resistant Staphylococcus aureus (MRSA).
  
  
  RESULTS
  Most of the cements showed burst release followed by low-level continuous release, whereas the coated granules showed high burst release for 24 h. After release the peptide was active (in nine of 12 materials) and intact.
  
  
  CONCLUSIONS
  Different release profiles may be obtained by choosing the appropriate carrier, which supports the feasibility of biodegradable carriers releasing AMPs against resistant infections.
mesh_terms: D001673:Biodegradation, Environmental; D018786:Bone Substitutes / Q000737:chemistry*; D002130:Calcium Phosphates / Q000737:chemistry*; D016503:Drug Delivery Systems / Q000379:methods*; D006801:Humans; D007781:Lactoferrin; D013058:Mass Spectrometry; D016106:Methicillin Resistance; D010446:Peptide Fragments / Q000737:chemistry* / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects*
chemical_list: D018786:Bone Substitutes; D002130:Calcium Phosphates; D010446:Peptide Fragments; C485828:alpha-tricalcium phosphate; C466658:lactoferrin (1-11), human; C485830:tetracalcium phosphate; C485838:calcium phosphate, monobasic, anhydrous; C020243:calcium phosphate; D007781:Lactoferrin; C485829:calcium phosphate, dibasic, anhydrous