title: Nourish and nurture: development of a nutrient ocular lubricant.
abstract: OBJECTIVE
  The authors aimed to produce a new tear substitute capable of providing both lubrication and nutrition, based on a novel nutrient-containing therapeutic ocular surface medium (TOSM).
  
  
  METHODS
  Viscous substances, including hypromellose (HPMC), carbopol, and sodium hyaluronate (SH) were added to the TOSM at various concentrations. Three commercial preservative-free artificial tear substitutes, Hypromellose (Pharmacy of Moorfields Eye Hospital, London, UK), Thilo-Tears (a carbomer; Alcon Pharma GmbH, Freiburg, Germany), and Vislube (a hyaluronate; Chemedica AG, Munich, Germany) were used as control preparations. Their viscosity and surface tension were measured. Human corneal (HCE-T) and conjunctival (IOBA-NHC) cell lines were used to investigate cell proliferation and viability in response to the formulations by means of a luminescence-based ATP assay and a calcein AM/EthD-1 assay.
  
  
  RESULTS
  HPMC, carbopol, and SH increased the viscosity of TOSM significantly. The surface tension of TOSM was reduced by HPMC, but not by carbopol or SH. TOSM-HPMC supported cell proliferation and viability better than TOSM-carbopol and TOSM-SH. TOSM-HPMC and TOSM-carbopol supported cell proliferation significantly better than the corresponding commercial artificial tears. However, TOSM-Vislube supported cell growth significantly better than TOSM-SH.
  
  
  CONCLUSIONS
  TOSM-HPMC showed superior lubricant and nutrient properties with moderate viscosity and little cytotoxicity. It thus could be an ideal nutrient and lubricant tear substitute for dry eyes and should be evaluated in a clinical study.
authors.affiliation: Department of Ophthalmology, University of Lübeck, Lübeck, Germany.
authors.forename: Lei
authors.initials: L
authors.lastname: Liu
authors.forename: John
authors.initials: J
authors.lastname: Tiffany
authors.forename: Zexu
authors.initials: Z
authors.lastname: Dang
authors.forename: John K G
authors.initials: JK
authors.lastname: Dart
authors.forename: Stephanie L
authors.initials: SL
authors.lastname: Watson
authors.forename: Julie T
authors.initials: JT
authors.lastname: Daniels
authors.forename: Gerd
authors.initials: G
authors.lastname: Geerling
mesh_terms: D000180:Acrylic Resins; D000255:Adenosine Triphosphate / Q000378:metabolism; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival; D003228:Conjunctiva / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004848:Epithelium; D019573:Epithelium, Corneal / Q000187:drug effects / Q000378:metabolism; D005452:Fluoresceins / Q000378:metabolism; D006801:Humans; D006820:Hyaluronic Acid / Q000737:chemistry / Q000633:toxicity; D006863:Hydrogen-Ion Concentration; D065347:Hypromellose Derivatives; D054327:Lubricants; D008747:Methylcellulose / Q000031:analogs & derivatives / Q000737:chemistry / Q000633:toxicity; D009747:Nutritional Physiological Phenomena; D009883:Ophthalmic Solutions / Q000737:chemistry* / Q000633:toxicity*; D009994:Osmolar Concentration; D011145:Polyvinyls / Q000737:chemistry / Q000633:toxicity; D013500:Surface Tension; D014783:Viscosity
chemical_list: D000180:Acrylic Resins; D005452:Fluoresceins; D054327:Lubricants; D009883:Ophthalmic Solutions; D011145:Polyvinyls; C006912:carboxypolymethylene; C085925:calcein AM; D065347:Hypromellose Derivatives; D000255:Adenosine Triphosphate; D006820:Hyaluronic Acid; D008747:Methylcellulose