title: Ultrasound-enhanced ocular delivery of dexamethasone sodium phosphate: an in vivo study.
abstract: BACKGROUND
  The eye's unique anatomy and its physiological and anatomical barriers can limit effective drug delivery into the eye.
  
  
  METHODS
  An in vivo study was designed to determine the effectiveness and safety of ultrasound application in enhancing drug delivery in a rabbit model. Permeability of a steroid ophthalmic drug, dexamethasone sodium phosphate, was investigated in ultrasound- and sham-treated cases. For this study, an eye cup filled with dexamethasone sodium phosphate was placed on the cornea. Ultrasound was applied at intensity of 0.8 W/cm(2) and frequency of 400 or 600 kHz for 5 min. The drug concentration in aqueous humor samples, collected 90 min after the treatment, was determined using chromatography methods. Light microscopy observations were done to determine the structural changes in the cornea as a result of ultrasound application.
  
  
  RESULTS
  An increase in drug concentration in aqueous humor samples of 2.8 times (p < 0.05) with ultrasound application at 400 kHz and 2.4 times (p < 0.01) with ultrasound application at 600 kHz was observed as compared to sham-treated samples. Histological analysis showed that the structural changes in the corneas exposed to ultrasound predominantly consisted of minor epithelial disorganization.
  
  
  CONCLUSIONS
  Ultrasound application enhanced the delivery of an anti-inflammatory ocular drug, dexamethasone sodium phosphate, through the cornea in vivo. Ultrasound-enhanced ocular drug delivery appears to be a promising area of research with a potential future application in a clinical setting.
authors.affiliation: Department of Electrical and Computer Engineering, George Washington University, Washington, DC 20052, USA.
authors.forename: Marjan
authors.initials: M
authors.lastname: Nabili
authors.affiliation: Department of Electrical and Computer Engineering, George Washington University, Washington, DC 20052, USA.
authors.forename: Aditi
authors.initials: A
authors.lastname: Shenoy
authors.affiliation: Department of Electrical and Computer Engineering, George Washington University, Washington, DC 20052, USA.
authors.forename: Shawn
authors.initials: S
authors.lastname: Chawla
authors.affiliation: Department of Ophthalmology, George Washington University, Washington, DC 20052, USA.
authors.forename: Sankaranarayana
authors.initials: S
authors.lastname: Mahesh
authors.affiliation: Department of Ophthalmology, George Washington University, Washington, DC 20052, USA.
authors.forename: Ji
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Ophthalmology, George Washington University, Washington, DC 20052, USA.
authors.forename: Craig
authors.initials: C
authors.lastname: Geist
authors.affiliation: Department of Electrical and Computer Engineering, George Washington University, Washington, DC 20052, USA.
authors.forename: Vesna
authors.initials: V
authors.lastname: Zderic
keywords: Cornea; Dexamethasone sodium phosphate; Drug delivery; Ocular diseases; Sonophoresis; Therapeutic ultrasound