Enhanced Intestinal Absorption of Cyclosporine in Rats Through the Reduction of Emulsion Droplet Size

Bryan D. Tarr, Samuel H. Yalkowsky

Research output: Contribution to journalArticlepeer-review

199 Scopus citations


The intestinal absorption of cyclosporine was measured in situ in rats using an olive oil emulsion prepared by either stirring or homogenization. The surface area of the homogenized dosage form was twice that of the stirred dosage form. The apparent permeability of cyclosporine from the homogenized emulsion was about twice that of the emulsion prepared by stirring. The examination of absorption in different intestinal segment lengths suggested the presence of an “absorption window.” The absorption of cyclosporine appeared to be concentration independent and, therefore, non-carrier mediated. The dependence of absorption upon the intestinal perfusion rate suggested that the stagnant aqueous layer is the rate-limiting barrier in cyclosporine absorption. These results indicate that the bioavailability of cyclosporine administered in an emulsion can possibly be increased by enhancing its rate of absorption through the reduction of droplet size.

Original languageEnglish (US)
Pages (from-to)40-43
Number of pages4
JournalPharmaceutical Research: An Official Journal of the American Association of Pharmaceutical Scientists
Issue number1
StatePublished - Jan 1989


  • cyclosporine
  • emulsion dosage form
  • intestinal absorption

ASJC Scopus subject areas

  • Biotechnology
  • Molecular Medicine
  • Pharmacology
  • Pharmaceutical Science
  • Organic Chemistry
  • Pharmacology (medical)


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