May 2008
Volume 49, Issue 13
Free
ARVO Annual Meeting Abstract  |   May 2008
An ex vivo Model Using High Throughput Cassette Dosing, LC/MS/MS Analysis, and Microdialysis to Assess Corneal Permeability of Eight Beta-Blockers: Comparison With Isolated Corneal Transport Studies
Author Affiliations & Notes
  • R. S. Kadam
    Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska
  • J. Hejkal
    Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska
  • H. F. Edelhauser
    Opthalomology, Emory Eye Center, Emory University, Atlanta, Georgia
  • U. B. Kompella
    Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, Nebraska
  • Footnotes
    Commercial Relationships  R.S. Kadam, None; J. Hejkal, None; H.F. Edelhauser, None; U.B. Kompella, None.
  • Footnotes
    Support  NIH grants R24 EY017045 and R21 EY017360
Investigative Ophthalmology & Visual Science May 2008, Vol.49, 3188. doi:
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      R. S. Kadam, J. Hejkal, H. F. Edelhauser, U. B. Kompella; An ex vivo Model Using High Throughput Cassette Dosing, LC/MS/MS Analysis, and Microdialysis to Assess Corneal Permeability of Eight Beta-Blockers: Comparison With Isolated Corneal Transport Studies. Invest. Ophthalmol. Vis. Sci. 2008;49(13):3188.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract

Purpose: : Beta-blockers and isolated cornea or corneal cell culture models are routinely used to study the influence of lipophilicity on corneal drug permeation. The purpose of this study was to establish an ex vivo bovine eye model employing cassette eye drop dosing, LC/MS/MS analysis, and microdialysis to determine corneal beta-blocker penetration and to compare the results with isolated cornea model.

Methods: : A cassette of eight beta-blockers with varying lipophilicities solubilized in assay buffer (pH 7.4) was used for eye drop administration in ex vivo studies and donor solutions in isolated corneal transport studies. The cassette included the following beta-blockers: sotalol, atenolol, nadolol, pindolol, metoprolol, timolol, betaxolol, and propranolol. In both studies, samples were collected up to 6 hours. The penetration of beta-blockers after topical application as a multiple-dose cassette eye drop was evaluated by microdialysis in the anterior chamber of an ex vivo bovine eye model (37 oC) using linear microdialysis probe (10 mm). In ex vivo studies, as an initial approach, we assessed penetration from multiple 50 µl drug drops applied every 30 minutes throughout the study, with 15 min intermittent blank buffer drops. In-vitro transport of beta-blocker cassette across isolated bovine corneas was also assessed. An LC/MS/MS method using Q-trap LC-MS/MS (positive ionization mode) was developed and validated for high-throughput cassette analysis of beta-blockers

Results: : The LCMS method for beta-blockers has short run-time (13 min) and is highly specific for the beta-blockers with good sensitivity (LOD: 10 ng/ml), accuracy (85-110 %), and reproducibility (RSD < 10 %). The beta-blocker penetration (µg/min) in the ex vivo model correlated well with their permeability (Papp, cm/sec) across isolated cornea (R2 = 0.92), with the delivery generally increasing with an increase in lipophilicity. Further, isolated bovine corneal permeabilities, although lower, correlated well with previously reported rabbit corneal permeabilities (R2 = 0.96) for five beta-blockers in common, after excluding propranolol, which exhibited much lower permeability across bovine cornea.

Conclusions: : Cassette dosing in an ex vivo model that reflects normal corneal architecture is a useful method for corneal drug penetration studies. Such an approach, by increasing throughput, can potentially minimize animal usage and cost.

Keywords: anterior chamber • ion transporters • anterior segment 
×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×