title: The effect of contact lens materials on disinfection activity of polyquaternium-1 and myristamidopropyl dimethylamine multipurpose solution against Staphylococcus aureus.
abstract: OBJECTIVE
  This study examined the interaction of seven different lens materials with a multipurpose solution (MPS) containing the disinfectants polyquaternium-1 (0.001%) and myristamidopropyl dimethylamine (0.0005%). The objective of this study was to determine whether the different lens materials affect the concentration of a disinfectant in this commercially available MPS and the efficacy of the disinfectant against Staphylococcus aureus.
  
  
  METHODS
  Silicone hydrogel lenses (galyfilcon A, senofilcon A, comfilcon A, enfilcon A, balafilcon A, and lotrafilcon B) and a conventional hydrogel lens (etafilcon A) were soaked in polypropylene lens cases filled with commercially available MPS containing 0.001% polyquaternium-1 and 0.0005% myristamidopropyl dimethylamine for 6, 12, 24, 72, and 168 hours. Empty lens cases were also filled with MPS. After each time point, solutions from cases containing the seven types of lenses and controls were assayed for activity against S. aureus according to International Standards Organization 14729 standard with modifications. Test solutions were analyzed for polyquaternium-1 and myristamidopropyl dimethylamine concentration at each time point.
  
  
  RESULTS
  The concentration of polyquaternium-1 and myristamidopropyl dimethylamine remaining in the lens cases was reduced only slightly over time. Storage with the lenses did not adversely affect biocidal efficacy of the solution, and in some cases, it was significantly better (P=0.0029).
  
  
  CONCLUSIONS
  The efficacy of this polyquaternium-1 and myristamidopropyl dimethylamine MPS to kill S. aureus was not adversely affected by the presence of lens materials soaking in the cases. Thus, current methods for performing solution antimicrobial testing should be reevaluated.
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: K Scott
authors.initials: KS
authors.lastname: Phillips
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: D015169:Colony Count, Microbial; D018639:Contact Lens Solutions / Q000032:analysis / Q000494:pharmacology*; D003263:Contact Lenses, Hydrophilic / Q000382:microbiology*; D004202:Disinfectants / Q000032:analysis / Q000494:pharmacology; D004203:Disinfection; D015818:Eye Infections, Bacterial / Q000517:prevention & control; D020100:Hydrogels; D011108:Polymers / Q000032:analysis / Q000494:pharmacology*; D011437:Propylamines / Q000032:analysis / Q000494:pharmacology*; D012828:Silicones; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000302:isolation & purification
chemical_list: D018639:Contact Lens Solutions; D004202:Disinfectants; D020100:Hydrogels; D011108:Polymers; D011437:Propylamines; D012828:Silicones; C058655:polyquaternium 1; C401661:myristamidopropyl dimethylamine