title: The bioavailability of mupirocin in nasal secretions in vitro.
abstract: OBJECTIVE
  To determine the bioavailability of mupirocin in human nasal secretions and to assess whether the contents of nasal secretions interact appreciably with this antibiotic.
  
  
  METHODS
  The comparative bioavailability of mupirocin and chlorhexidine in nasal secretions was determined by bioassay after one, four, and eight hours of incubation with pooled secretions from three subjects. The interaction of mupirocin with nasal secretions was characterised by matrix assisted laser desorption time of flight mass spectrometry (MALDI-TOF).
  
  
  RESULTS
  MALDI-TOF analysis showed that mupirocin was not absorbed by the main fraction of pooled nasal secretions and should remain active. In bioassay, mupirocin retained 100% of its antistaphylococcal activity in nasal secretions, whereas chlorhexidine was significantly reduced from 100 mg/litre to 1.5 mg/litre and from 1000 mg/litre to 38.5 mg/litre, irrespective of incubation time.
  
  
  CONCLUSIONS
  The high bioavailability of mupirocin in nasal secretions results from the lack of appreciable molecular interactions.
authors.affiliation: South London Public Health Laboratory and Department of Infection, Guy's, King's, and St Thomas's School of Medicine, King's Denmark Hill Campus, Bessemer Road, London SE5 9PJ, UK. robert.l.hill@kcl.ac.uk
authors.forename: R L R
authors.initials: RL
authors.lastname: Hill
mesh_terms: D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics*; D001681:Biological Assay; D001682:Biological Availability; D002710:Chlorhexidine / Q000493:pharmacokinetics; D005260:Female; D006801:Humans; D008297:Male; D009093:Mucus / Q000378:metabolism*; D016712:Mupirocin / Q000493:pharmacokinetics*; D009297:Nasal Mucosa / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D000900:Anti-Bacterial Agents; D016712:Mupirocin; D002710:Chlorhexidine