title: Ciprofloxacin interaction with silicon-based and conventional hydrogel contact lenses.
abstract: OBJECTIVE
  Hydrogel contact lenses can be used as bandage lenses to protect the corneal surface after injury. The use of novel silicon-based hydrogel lens materials as bandage lenses has not gained widespread acceptance. As a first step toward advocating their usefulness as bandage lenses, their interaction with ocular pharmaceuticals must be understood because topical agents are often administered in conjunction with bandage lenses.
  
  
  METHODS
  The in vitro uptake and release of ciprofloxacin from silicone-based hydrogel (SH) and conventional pHEMA-based (CH) hydrogel contact lenses was examined by spectrophotometric evaluation of the drug concentration in saline solution.
  
  
  RESULTS
  The hydrogel contact lenses tested showed similar drug uptake (average 1800 microg/lens) but different levels of drug release. Multiphoton laser microscopy indicated that ciprofloxacin was distributed throughout the lens thickness, with higher levels of drug at the surface owing to drug precipitation. The drug adsorption onto the lenses was partially reversible. The SH lenses released a lower amount of drug than CH lenses (72 vs. 168 microg/lens). Ionic lenses released less drug than non-ionic lenses (127 vs. 151 microg/lens).
  
  
  CONCLUSIONS
  The differences in ciprofloxacin uptake and release between SH and CH materials may not be clinically significant because the amount of drug released from all lenses would be above the MIC(90) of ciprofloxacin for common ocular pathogens. These results indicate that material properties have a significant impact on drug-lens interactions.
authors.affiliation: Department of Chemical Engineering, School of Optometry, University of Waterloo, Ontario, Canada.
authors.forename: C C S
authors.initials: CC
authors.lastname: Karlgard
authors.forename: L W
authors.initials: LW
authors.lastname: Jones
authors.forename: C
authors.initials: C
authors.lastname: Moresoli
mesh_terms: D000327:Adsorption; D000890:Anti-Infective Agents / Q000378:metabolism*; D002939:Ciprofloxacin / Q000378:metabolism*; D003263:Contact Lenses, Hydrophilic; D004347:Drug Interactions; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D011102:Polyhydroxyethyl Methacrylate; D012826:Silicone Elastomers
chemical_list: D000890:Anti-Infective Agents; D012826:Silicone Elastomers; D011102:Polyhydroxyethyl Methacrylate; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D002939:Ciprofloxacin