title: Physical entrapment of hyaluronic acid during synthesis results in extended release from model hydrogel and silicone hydrogel contact lens materials.
abstract: OBJECTIVE
  This study was designed to assess the duration of hyaluronic acid (HA) release from model contact lens materials when HA was physically incorporated into the hydrogel during synthesis and to assess the effects of the HA release on lysozyme sorption.
  
  
  METHODS
  Model conventional and silicone hydrogel contact lens materials containing HA of various molecular weights as a releasable wetting agent were prepared. The HA was released into phosphate-buffered saline and MilliQ water, and the release was monitored using ultraviolet spectroscopy. Hyaluronic acid release was quantified by enzyme-linked immunosorbent assay. The effect of the releasable HA on lysozyme sorption to the materials was also analyzed using 125-I-labeled protein.
  
  
  RESULTS
  Hyaluronic acid loaded into the materials using this method could be released from conventional hydrogel materials for 21 days; the model silicone hydrogels showed release of more than 7 weeks. With one exception, the releasable HA decreased lysozyme sorption.
  
  
  CONCLUSIONS
  Hyaluronic acid physically incorporated into contact lens materials during synthesis may therefore be released for extended periods of time of up to 7 weeks. Hyaluronic acid release leads to decreased protein adsorption in general. This method has potential for modification of conventional and silicone hydrogel lenses with releasable HA as a wetting agent.
authors: School of Biomedical Engineering, McMaster University, Hamilton, Ontario, Canada.
authors: Andrea
authors: A
authors: Weeks
authors: Lakshman N
authors: LN
authors: Subbaraman
authors: Lyndon
authors: L
authors: Jones
authors: Heather
authors: H
authors: Sheardown
mesh_terms: D000327:Adsorption / Q000187:drug effects; D003263:Contact Lenses, Hydrophilic; D003692:Delayed-Action Preparations; D006820:Hyaluronic Acid / Q000737:chemistry* / Q000494:pharmacology; D020100:Hydrogels / Q000737:chemistry*; D008954:Models, Biological; D009113:Muramidase / Q000378:metabolism
chemical_list: D003692:Delayed-Action Preparations; D020100:Hydrogels; D006820:Hyaluronic Acid; D009113:Muramidase