title: Contact lenses as a platform for ocular drug delivery.
abstract: BACKGROUND
  Most ophthalmic drugs are delivered through eye drops even though only about 1 - 5% of the drug reaches the target tissue and the patient compliance is not good. Drug-eluting contact lenses could significantly increase bioavailability, reduce side effects and improve patient compliance.
  
  
  METHODS
  Recent research on drug-eluting contact lenses has focused on increasing the release duration through molecular imprinting, dispersion of barriers or nanoparticles, increasing drug binding to the polymer, sandwiching a PLGA (poly[lactic-co-glycolic acid]) layer in a lens and developing novel materials. This review covers all these studies with a specific focus on the transport mechanisms and advantages and disadvantages of each approach.
  
  
  CONCLUSIONS
  The main reason for prior failures was the short duration of release from the lenses. The new technologies can provide extended drug release for hours to days. The in vivo animal and clinical studies have proven the safety and efficacy of drug-eluting contact lenses, while showing considerable improvements compared to eye drops. The future appears to be promising but several challenges remain such as processing and storage issues, regulatory hurdles, high costs of clinical studies, potential lack of acceptance by the elderly, etc.
authors.affiliation: University of Florida, Department of Chemical Engineering , 1006 Center Drive, Gainesville, FL 32611 , USA +1 352 392 2592 ; +1 352 392 9513 ; E-mail: chauhan@che.ufl.edu.
authors.forename: Lokendrakumar C
authors.initials: LC
authors.lastname: Bengani
authors.forename: Kuan-Hui
authors.initials: KH
authors.lastname: Hsu
authors.forename: Samuel
authors.initials: S
authors.lastname: Gause
authors.forename: Anuj
authors.initials: A
authors.lastname: Chauhan
mesh_terms: D000818:Animals; D000869:Anterior Eye Segment / Q000187:drug effects; D001682:Biological Availability; D002626:Chemistry, Pharmaceutical / Q000379:methods; D003261:Contact Lenses; D016503:Drug Delivery Systems; D006801:Humans; D019344:Lactic Acid / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry; D009883:Ophthalmic Solutions / Q000008:administration & dosage*; D011100:Polyglycolic Acid / Q000737:chemistry; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer
chemical_list: D009883:Ophthalmic Solutions; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid