title: Release of vancomycin and gentamicin from a contact lens versus a fibrin coating applied to a contact lens.
abstract: OBJECTIVE
  To develop a contact lens capable of releasing antibiotics for a minimum of 8 hours for the treatment of bacterial keratitis.
  
  
  METHODS
  Fibrin gel was loaded with vancomycin or gentamicin and then shaped into a curved disc. The disc was then used to coat the surface of a commercial contact lens or was sealed between two lenses. Separate contact lenses were soaked in solutions of vancomycin or gentamicin. The in vitro release kinetics for each system was determined using PBS at 37°C and a particle-enhanced turbidimetric inhibition immunoassay. The bioactivity of the antibiotics released from the fibrin was confirmed by using a microbiological assay.
  
  
  RESULTS
  Vancomycin and gentamicin were released at similar rates from soaked contact lenses and a coating of fibrin gel; however, the amounts of antibiotic delivered by the two systems differed considerably. The fibrin coating released over three times more gentamicin but less than one-fifth that of the lenses soaked in vancomycin. When fibrin was encapsulated between two contact lenses, significantly more controlled release was observed. For all systems, bactericidal amounts of vancomycin and gentamicin were released throughout the three-day testing period.
  
  
  CONCLUSIONS
  As a delivery system, fibrin gel loaded with gentamicin performs better than contact lenses soaked in gentamicin. The opposite is true for vancomycin, where soaked lenses outperform fibrin gel. These systems could potentially be used as a treatment for bacterial keratitis.
authors.affiliation: Centre for Brain Repair, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Alex J T
authors.initials: AJ
authors.lastname: Hyatt
authors.forename: Madhavan S
authors.initials: MS
authors.lastname: Rajan
authors.forename: Keith
authors.initials: K
authors.lastname: Burling
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Ellington
authors.forename: Alessia
authors.initials: A
authors.lastname: Tassoni
authors.forename: Keith R
authors.initials: KR
authors.lastname: Martin
mesh_terms: D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics; D020099:Coated Materials, Biocompatible; D003263:Contact Lenses, Hydrophilic; D004867:Equipment Design; D015818:Eye Infections, Bacterial / Q000378:metabolism / Q000517:prevention & control; D005337:Fibrin; D005839:Gentamicins / Q000493:pharmacokinetics*; D006801:Humans; D007634:Keratitis / Q000378:metabolism / Q000517:prevention & control; D014640:Vancomycin / Q000493:pharmacokinetics*
chemical_list: D000900:Anti-Bacterial Agents; D020099:Coated Materials, Biocompatible; D005839:Gentamicins; D014640:Vancomycin; D005337:Fibrin