1. Academic Validation
  2. Alteration of the intravenous pharmacokinetics of a synthetic ozonide antimalarial in the presence of a modified cyclodextrin

Alteration of the intravenous pharmacokinetics of a synthetic ozonide antimalarial in the presence of a modified cyclodextrin

  • J Pharm Sci. 2006 Feb;95(2):256-67. doi: 10.1002/jps.20534.
Susan A Charman 1 Christine S Perry Francis C K Chiu Kylie A McIntosh Richard J Prankerd William N Charman
Affiliations

Affiliation

  • 1 Centre for Drug Candidate Optimisation, Victorian College of Pharmacy, Monash University (Parkville Campus), Parkville, Victoria, Australia. susan.charman@vcp.monash.edu.au
Abstract

The pharmacokinetic profile and renal clearance of a novel synthetic ozonide antimalarial (1) was found to be significantly altered when intravenously administered to rats as a cyclodextrin-based formulation (0.1 M Captisol, a sulfobutylether beta-cyclodextrin derivative (SBE(7)-beta-CD)) compared to a cyclodextrin-free isotonic buffered glucose formulation. There was an 8.5-fold decrease in the steady-state blood volume of distribution, a 6.6-fold decrease in the mean residence time and a greater than 200-fold increase in renal clearance of 1 when administered in the cyclodextrin formulation. Analysis of the whole blood and plasma concentration profiles revealed an essentially constant blood to plasma ratio when 1 was administered in the cyclodextrin-free formulation, whereas this ratio changed as a function of time when administered in the presence of the cyclodextrin derivative. It is postulated that the observed differences were due to a very strong complexation interaction between 1 and the cyclodextrin, resulting in a slow dissociation of the complex in vivo, and altered distribution and excretion profiles. Preliminary studies using isothermal titration calorimetry (ITC) indicated that the association constant for the 1/Captisol complex was approximately two orders of magnitude higher than reported for typical drug/cyclodextrin complexes.

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