title: Effects of a Hyaluronic Acid/Hydroxypropyl Guar Artificial Tear Solution on Protection, Recovery, and Lubricity in Models of Corneal Epithelium.
abstract: OBJECTIVE
  Hydroxypropyl guar (HPG) and hyaluronic acid (HA) have been individually shown to improve dry eye symptoms. The purpose of this in vitro study was to assess the potential benefits of a new lubricant eye drop formulation containing the demulcents propylene glycol and polyethylene glycol and an HA/HPG dual polymer in models of the human corneal epithelium.
  
  
  METHODS
  Cultured human corneal epithelial or corneal-limbal epithelial cells were treated with the HA/HPG dual-polymer formulation or single-polymer formulations containing either HPG or HA. Desiccation protection by cell hydration and surface retention was assessed using cell viability assays. Sodium fluorescein permeability, transepithelial resistance, and cell viability assays were conducted using pretreated cells exposed to a surfactant/detergent insult to evaluate cell and cell barrier protection. Surface lubricity was assessed in tribological experiments of pericardium-pericardium friction.
  
  
  RESULTS
  Hydration protection against desiccation and protection by surface retention were significantly greater with the HA/HPG formulation versus HPG or HA (P<0.001) alone and with HPG versus HA (P ≤ 0.016). Fluorescein permeability and transepithelial resistance assays demonstrated significantly better cell and barrier protection from surfactant insult with HA/HPG versus the single-polymer formulations (P ≤ 0.01). After insult, there were markedly more viable cells evident with HA/HPG compared with HPG or HA alone. HA/HPG and HPG reduced surface friction to a greater extent than HA (P ≤ 0.02) and maintained lubricity after the formulations were rinsed away.
  
  
  CONCLUSIONS
  HA/HPG provided effective hydration and lubrication and demonstrated prolonged retention of effect. HA/HPG may potentially promote desiccation protection and retention on the ocular surface.
authors.affiliation: Alcon Research, Ltd. , Fort Worth, Texas.
authors.forename: Rekha
authors.initials: R
authors.lastname: Rangarajan
authors.affiliation: Alcon Research, Ltd. , Fort Worth, Texas.
authors.forename: Brian
authors.initials: B
authors.lastname: Kraybill
authors.affiliation: Alcon Research, Ltd. , Fort Worth, Texas.
authors.forename: Abayomi
authors.initials: A
authors.lastname: Ogundele
authors.affiliation: Alcon Research, Ltd. , Fort Worth, Texas.
authors.forename: Howard A
authors.initials: HA
authors.lastname: Ketelson
mesh_terms: D002470:Cell Survival / Q000187:drug effects; D003315:Cornea / Q000166:cytology / Q000187:drug effects*; D018592:Cross-Over Studies; D004353:Drug Evaluation, Preclinical / Q000379:methods; D015352:Dry Eye Syndromes / Q000188:drug therapy / Q000517:prevention & control; D019573:Epithelium, Corneal / Q000166:cytology / Q000187:drug effects*; D006801:Humans; D006820:Hyaluronic Acid / Q000494:pharmacology*; D065346:Lubricant Eye Drops / Q000494:pharmacology*; D011092:Polyethylene Glycols / Q000494:pharmacology; D011134:Polysaccharides / Q000494:pharmacology*; D019946:Propylene Glycol / Q000494:pharmacology; D013501:Surface-Active Agents / Q000494:pharmacology; D016896:Treatment Outcome; D055675:Viscosupplements / Q000494:pharmacology*
chemical_list: D065346:Lubricant Eye Drops; D011134:Polysaccharides; D013501:Surface-Active Agents; D055675:Viscosupplements; C519976:hydroxypropyl guar; D011092:Polyethylene Glycols; D019946:Propylene Glycol; D006820:Hyaluronic Acid