Triprotic acid-base microequilibria and pharmacokinetic sequelae of cetirizine

Attila Marosi, Zsuzsanna Kovács, Szabolcs Béni, József Kökösi, Béla Noszál

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12 Citations (Scopus)


1H NMR-pH titrations of cetirizine, the widely used antihistamine and four related compounds were carried out and the related 11 macroscopic protonation constants were determined. The interactivity parameter between the two piperazine amine groups was obtained from two symmetric piperazine derivatives. Combining these two types of datasets, all the 12 microconstants and derived tautomeric constants of cetirizine were calculated. Upon this basis, the conflicting literature data of cetirizine microspeciation were clarified, and the pharmacokinetic absorption-distribution properties could be interpreted. The pH-dependent distribution of the microspecies is provided.

Original languageEnglish
Pages (from-to)321-328
Number of pages8
JournalEuropean Journal of Pharmaceutical Sciences
Issue number3-4
Publication statusPublished - Jun 28 2009



  • Cetirizine
  • Indicator molecule
  • Interactivity parameter
  • Microscopic protonation constant
  • NMR-pH titration
  • Pharmacokinetics
  • Piperazine derivatives

ASJC Scopus subject areas

  • Pharmaceutical Science

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