title: In vitro comparative toxicology of polyquad-preserved and benzalkonium chloride-preserved travoprost/timolol fixed combination and latanoprost/timolol fixed combination.
abstract: OBJECTIVE
  To compare, in vitro, the cytotoxicity profile of a new formulation of travoprost 0.004%/timolol 0.5% fixed combination ophthalmic solution preserved with polyquaternium-1 0.001% (travoprost/timolol PQ) instead of benzalkonium chloride (BAK) with (1) commercially available travoprost 0.004%/timolol 0.5% fixed combination ophthalmic solution (travoprost/timolol BAK), (2) commercially available latanoprost 0.005%/timolol 0.5% fixed combination ophthalmic solution (latanoprost/timolol BAK), and (3) their associated BAK concentrations.
  
  
  METHODS
  Compounds tested on Wong-Kilbourne-derived human conjunctival epithelial cells: (1) phosphate-buffered saline, (2) polyquaternium-1 0.001% (Polyquad(®), PQ), (3) travoprost/timolol PQ, (4) travoprost/timolol BAK with 0.015% BAK (DuoTrav(®)), (5) BAK 0.015%, (6) latanoprost/timolol BAK with 0.020% BAK (Xalacom(®)), and (7) BAK 0.020%. Toxicological assays were used to assess cell viability [neutral red (NR), Alamar blue (AB)], apoptosis (YO-PRO-1, Hoechst 33342), and oxidative stress (H(2)DCF-DA, hydroethidine). The apoptosis and oxidative stress assays were each reported according to cell viability as observed with NR and AB (totaling 10 analyses per treatment).
  
  
  RESULTS
  The NR and AB assays demonstrated that cells incubated with travoprost/timolol PQ had significantly better viability than cells incubated with latanoprost/timolol BAK, travoprost/timolol BAK, BAK 0.015%, and BAK 0.020% (P<0.0001 for all). As assessed with YO-PRO-1 and Hoechst 33342 relative to cell viability determined with NR or AB, travoprost/timolol PQ produced significantly less apoptosis than travoprost/timolol BAK and latanoprost/timolol BAK and their respective BAK concentrations alone (P<0.0001 for all). Also, travoprost/timolol BAK induced less apoptosis than latanoprost/timolol BAK (P<0.0001). As assessed with H(2)DCF-DA as a ratio to NR or AB, all of the compounds without BAK (phosphate-buffered saline, PQ 0.001%, and travoprost/timolol PQ) and travoprost/timolol BAK produced significantly less reactive oxygen species than latanoprost/timolol BAK (P<0.0001 for all). As assessed with hydroethidine as a ratio to NR or AB, travoprost/timolol PQ produced significantly fewer superoxide anions than latanoprost/timolol BAK (P<0.0001). In contrast, release of superoxide anions (hydroethidine method) after incubation with travoprost/timolol BAK was not significantly different from incubation with latanoprost/timolol BAK or travoprost/timolol PQ.
  
  
  CONCLUSIONS
  Travoprost/timolol PQ may be better for ocular surface health than either BAK preserved formulations of latanoprost/timolol or travoprost/timolol.
authors.affiliation: Institut National de la Santé et de la Recherche Médicale, U968, Paris, France. francoise.brignole-baudouin@parisdescartes.fr
authors.forename: Françoise
authors.initials: F
authors.lastname: Brignole-Baudouin
authors.forename: Luisa
authors.initials: L
authors.lastname: Riancho
authors.forename: Hong
authors.initials: H
authors.lastname: Liang
authors.forename: Zaki
authors.initials: Z
authors.lastname: Nakib
authors.forename: Christophe
authors.initials: C
authors.lastname: Baudouin
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D001548:Benzalkonium Compounds / Q000633:toxicity*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D002626:Chemistry, Pharmaceutical; D002999:Clone Cells; D003008:Cloprostenol / Q000031:analogs & derivatives* / Q000633:toxicity; D003228:Conjunctiva / Q000187:drug effects* / Q000378:metabolism; D004338:Drug Combinations; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D000077338:Latanoprost; D009798:Ocular Hypertension / Q000188:drug therapy; D009883:Ophthalmic Solutions; D018384:Oxidative Stress / Q000187:drug effects; D011108:Polymers / Q000633:toxicity*; D011310:Preservatives, Pharmaceutical / Q000633:toxicity*; D011461:Prostaglandins F, Synthetic / Q000633:toxicity*; D013481:Superoxides / Q000378:metabolism; D013565:Sympatholytics / Q000633:toxicity; D013999:Timolol / Q000633:toxicity*; D000069557:Travoprost
chemical_list: D001548:Benzalkonium Compounds; D004338:Drug Combinations; D009883:Ophthalmic Solutions; D011108:Polymers; D011310:Preservatives, Pharmaceutical; D011461:Prostaglandins F, Synthetic; D013565:Sympatholytics; D013481:Superoxides; D003008:Cloprostenol; D000077338:Latanoprost; C058655:polyquaternium 1; D013999:Timolol; D000069557:Travoprost