In vitro and in vivo evaluation of a sulfobutyl ether β-cyclodextrin enabled etomidate formulation

Michelle P. McIntosh, Nancy Schwarting, Roger A. Rajewski

Research output: Contribution to journalArticleResearchpeer-review

34 Citations (Scopus)


In this study, we report the formulation and in vivo evaluation of etomidate in an aqueous solution using sulfobutyl ether-7 β-cyclodextrin (SBE-CD, Captisol®) as a solubilizing agent. The phase-solubility behavior of etomidate as a function of SBE-CD concentration was evaluated, and accelerated solution stability studies of 2 mg/mL etomidate in a 5% w/v SBE-CD solution were conducted. The intravenous administration of the SBE-CD etomidate formulation in dogs was compared with Amidate®, the commercial etomidate drug product formulated with propylene glycol as a cosolvent. The etomidate plasma concentration-time data were fit to a three-compartment mamillary model and the derived standard pharmacokinetic parameters were not statistically different between the two formulations (n = 4,p > 0.050). Concurrent pharmacodynamic analysis provided statistically equivalent maximum effects and median inhibitory concentrations for the two formulations. In vivo hemolysis after intravenous administration of Amidate® was 10-fold higher than the SBE-CD formulation. Whereas Amidate® cannot be given subcutaneously because of the cosolvent in the formulation, a 12 mg/mL aqueous solution of etomidate in 20% (w/v) SBE-CD was well tolerated by this route. The results suggest that the SBE-CD formulation is a viable clinical drug product with a reduced side-effect profile.

Original languageEnglish
Pages (from-to)2585-2594
Number of pages10
JournalJournal of Pharmaceutical Sciences
Issue number10
Publication statusPublished - 1 Jan 2004
Externally publishedYes


  • Bioequivalence
  • Complexation
  • Cyclodextrin
  • Pharmacodynamics
  • Pharmacokinetics

Cite this