title: Ocular drug delivery - a look towards nanobioadhesives.
abstract: BACKGROUND
  A major challenge emanating in the design of topical ophthalmic preparations is their short precorneal residence time. Retention of a drug delivery system in the front of the eye is thus desirable. One solution identified to address this concern is a retentive system that can preferably be delivered in a liquid drop form and ultimately remain attached to the corneal tissue owing to incorporation of a bioadhesive component. Forward-thinking approaches are required to achieve advancements in this approach for the attainment of an effective drug concentration at the site of action. Accordingly, several investigators have identified the benefits of nanotechnology-based drug delivery systems for ophthalmic drug delivery.
  
  
  METHODS
  A concerted effort was made to review critically all 'nanobioadhesives', that is, nanosystems designed for ocular drug delivery with the goal of attaining prolonged ocular retention, in a systematic, chronological manner, from their reported point of inception to the present.
  
  
  RESULTS
  A perspective on possible future trends in this growing field of ocular drug delivery is formulated.
  
  
  CONCLUSIONS
  The importance of and need for new developments in the field of ocular nanobioadhesives is emphasized.
authors.affiliation: University of the Witwatersrand, Department of Pharmacy and Pharmacology, 7 York Road, Parktown, 2193, Johannesburg, South Africa.
authors.forename: Lisa C
authors.initials: LC
authors.lastname: du Toit
authors.forename: Viness
authors.initials: V
authors.lastname: Pillay
authors.forename: Yahya E
authors.initials: YE
authors.lastname: Choonara
authors.forename: Thirumala
authors.initials: T
authors.lastname: Govender
authors.forename: Trevor
authors.initials: T
authors.lastname: Carmichael
mesh_terms: D000268:Adhesiveness; D000287:Administration, Topical; D000818:Animals; D016503:Drug Delivery Systems; D015195:Drug Design; D005128:Eye Diseases / Q000188:drug therapy; D006801:Humans; D053758:Nanoparticles; D036103:Nanotechnology / Q000379:methods*; D011108:Polymers / Q000737:chemistry; D013997:Time Factors
chemical_list: D011108:Polymers