title: Advances in ocular drug delivery: emphasis on the posterior segment.
abstract: BACKGROUND
  Recent advances in pharmacological therapies to treat ocular diseases such as glaucoma, age-related macular degeneration, diabetic macular edema and retinal vascular occlusions have greatly improved the prognosis for these diseases. Due to these advances in pharmacological therapy, there is a great deal of interest in minimally invasive delivery methods, which has generated rapid developments in the field of ocular drug delivery.
  
  
  METHODS
  This review will summarize currently available and recent developments for ocular drug delivery to both the anterior and posterior segments. Modes of delivery, including topical, systemic, transcleral/periocular and intravitreal, will be discussed and corresponding examples will be given. This review will highlight the advantages and disadvantages of each mode of delivery and discuss strategies to address these issues.
  
  
  CONCLUSIONS
  An ideal therapy should maintain effective levels of drug for the intended duration of treatment following a single application, yet a significant number of months of therapy may be required. There are numerous approaches under investigation to improve treatment options. From the use of novel biomaterial implants and depots for sustained release, to prodrug formations, to iontophoresis to improve drug delivery, the main emphasis will continue to be placed on less invasive, longer acting, sustained release formulations in the treatment of numerous ocular disorders.
authors: Illinois Institute of Technology, Department of Biomedical Engineering , Chicago, IL 60616 , USA kang-mieler@iit.edu.
authors: Jennifer J
authors: JJ
authors: Kang-Mieler
authors: Christian R
authors: CR
authors: Osswald
authors: William F
authors: WF
authors: Mieler
mesh_terms: D000818:Animals; D016503:Drug Delivery Systems; D006801:Humans; D009883:Ophthalmic Solutions / Q000008:administration & dosage*; D004364:Pharmaceutical Preparations / Q000008:administration & dosage*; D057972:Posterior Eye Segment / Q000187:drug effects*
chemical_list: D009883:Ophthalmic Solutions; D004364:Pharmaceutical Preparations
keywords: anterior segment delivery; drug delivery; eye; posterior segment delivery