title: Influence of permeant lipophilicity on permeation across human sclera.
abstract: OBJECTIVE
  The objectives of this study were to determine the effects of permeant lipophilicity on permeant uptake into and transport across human sclera for transscleral delivery.
  
  
  METHODS
  Model permeants with a wide range of lipophilicities were selected and studied with human sclera. Uptake experiments were carried out to measure permeant partitioning into the sclera. Transport experiments were performed in side-by-side diffusion cells, and the permeability coefficients and transport lag times of the permeants across the sclera were evaluated.
  
  
  RESULTS
  Permeants with higher lipophilicity showed higher partition coefficients to human sclera, and the apparent transport lag time also increased significantly as the permeant lipophilicity increased. No correlation between the permeability coefficients and lipophilicity of the model permeants was observed in this study with human sclera. A hypothesis on the different findings between the present and previous studies was proposed.
  
  
  CONCLUSIONS
  Permeants with higher lipophilicity exhibited stronger binding to human sclera and would therefore lead to larger permeant partitioning to the sclera and longer transport lag time. The steady-state permeability coefficients of the permeants were not significantly affected by permeant lipophilicity.
authors: Division of Pharmaceutical Sciences James L. Winkle College of Pharmacy, University of Cincinnati, 3225 Eden Avenue 136 HPB, Cincinnati, Ohio 45267, USA.
authors: He
authors: H
authors: Wen
authors: Jinsong
authors: J
authors: Hao
authors: S Kevin
authors: SK
authors: Li
mesh_terms: D000368:Aged; D006801:Humans; D008875:Middle Aged; D010539:Permeability; D012590:Sclera / Q000378:metabolism*