title: Phase-transition W/O Microemulsions for Ocular Delivery: Evaluation of Antibacterial Activity in the Treatment of Bacterial Keratitis.
abstract: OBJECTIVE
  Moxifloxacin (MXN) is widely prescribed for the treatment of bacterial keratitis. The conventional MXN solution has several limitations, including short precorneal residence time and poor intrastromal bioavailability, requiring frequent instillation of the drug to achieve the desired therapeutic effect. To circumvent this problem, the W/O (water-in-oil) microemulsion (ME) system was utilized for sustained release and improved precorneal retention.
  
  
  METHODS
  The pseudo-ternary phase diagrams were developed and various MEs were prepared using two non-ionic surfactants, Tween 80 and Span 20, with isopropyl myristate and acetate buffer. Physicochemical parameters, in vitro drug release and in vitro antibacterial activity were studied. The in vivo antimicrobial efficacy of optimized microemulsion (ME 10) was studied in an experiment on bacterial keratitis in rabbit eyes and compared with that of the marketed eye drops.
  
  
  RESULTS
  The optimized microemulsion (ME 10) displays as an average globule size of <40 nm. The developed MEs showed acceptable physico-chemical behaviour, good stability for 3 months and exhibited sustained drug release. Greater efficacy in experimental bacterial keratitis in rabbit eyes was also observed in comparison with marketed drug solution.
  
  
  CONCLUSIONS
  The developed MEs are a viable alternative to conventional eye drops, because of its ability to enhance bioavailability through its longer precorneal residence time and its ability to sustain the release of the drug.
authors.affiliation: a Institute of Pharmaceutical Sciences , Guru Ghasdas Vishwavidyalaya, Koni , Bilaspur , Chhattisgarh , India.
authors.forename: Shanni Kant
authors.initials: SK
authors.lastname: Bharti
authors.affiliation: a Institute of Pharmaceutical Sciences , Guru Ghasdas Vishwavidyalaya, Koni , Bilaspur , Chhattisgarh , India.
authors.forename: Karthikeyan
authors.initials: K
authors.lastname: Kesavan
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics; D003320:Corneal Ulcer / Q000188:drug therapy* / Q000382:microbiology; D016503:Drug Delivery Systems; D004655:Emulsions / Q000737:chemistry*; D004926:Escherichia coli / Q000187:drug effects; D015818:Eye Infections, Bacterial / Q000188:drug therapy* / Q000382:microbiology; D024841:Fluoroquinolones / Q000008:administration & dosage* / Q000737:chemistry; D006601:Hexoses / Q000737:chemistry; D046529:Microscopy, Electron, Transmission; D000077266:Moxifloxacin; D009226:Myristates / Q000737:chemistry; D009821:Oils / Q000737:chemistry; D010316:Particle Size; D044367:Phase Transition; D011136:Polysorbates / Q000737:chemistry; D011817:Rabbits; D013203:Staphylococcal Infections / Q000188:drug therapy* / Q000382:microbiology; D013211:Staphylococcus aureus / Q000187:drug effects; D014867:Water / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D004655:Emulsions; D024841:Fluoroquinolones; D006601:Hexoses; D009226:Myristates; D009821:Oils; D011136:Polysorbates; D014867:Water; C008205:isopropyl myristate; C014822:sorbitan monolaurate; D000077266:Moxifloxacin
keywords: Bacterial keratitis; Moxifloxacin; in vivo antibacterial; phase-transition microemulsion; rabbit eyes