title: The effects of contact lens materials on a multipurpose contact lens solution disinfection activity against Staphylococcus aureus.
abstract: OBJECTIVE
  To determine the effect of 8 different lens materials on polyhexamethylene biguanide (PHMB) concentration in multipurpose solution (MPS) levels over time and to determine the effect of lenses on lens solution microbial efficacy over time.
  
  
  METHODS
  Silicone hydrogel lenses and conventional hydrogel lenses were soaked in polypropylene lens cases filled with contact lens MPS containing 1 ppm PHMB for 6, 12, 24, 72, and 168 hours. Cases filled with the same solution without lenses were controls. After each time period, solutions from cases with the 8 types of lenses and controls were assayed for activity against Staphylococcus aureus according to International Organization for Standardization-14729 with modifications. Solutions were analyzed for PHMB concentration at each time point.
  
  
  RESULTS
  Some of the different lens materials significantly affected the PHMB concentration (P<0.0001) and the biocidal efficacy. Etafilcon A lenses significantly decreased PHMB levels after only 6 hours of lens soak time. The product lot of MPS used was also significant (P<0.0001). Enfilcon A, senofilcon A, and lotrafilcon B lenses did not significantly decrease PHMB levels.
  
  
  CONCLUSIONS
  The efficacy of MPS was affected by some lens materials and PHMB concentration. Lens materials differ in their effect on PHMB concentration and the subsequent efficacy of the MPS. Over time, some lens materials can significantly reduce the PHMB concentration and the MPS's microbial activity against S. aureus.
authors.affiliation: Division of Biology, Food and Drug Administration, Food and Drug Administration, Center for Devices and Radiological Health, Office of Device Evaluation, Silver Spring, MD, USA. mshoff@hodges.edu
authors.forename: Megan E
authors.initials: ME
authors.lastname: Shoff
authors.forename: Anne D
authors.initials: AD
authors.lastname: Lucas
authors.forename: Jennifer N
authors.initials: JN
authors.lastname: Brown
authors.forename: Victoria M
authors.initials: VM
authors.lastname: Hitchins
authors.forename: Malvina B
authors.initials: MB
authors.lastname: Eydelman
mesh_terms: D001645:Biguanides / Q000032:analysis; D015169:Colony Count, Microbial; D018639:Contact Lens Solutions / Q000032:analysis / Q000494:pharmacology*; D003263:Contact Lenses, Hydrophilic / Q000382:microbiology*; D004202:Disinfectants / Q000032:analysis / Q000494:pharmacology; D015818:Eye Infections, Bacterial / Q000517:prevention & control; D020100:Hydrogels; D012828:Silicones; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000302:isolation & purification
chemical_list: D001645:Biguanides; D018639:Contact Lens Solutions; D004202:Disinfectants; D020100:Hydrogels; D012828:Silicones; C031233:polihexanide