Characterization of potential NMDA and cholecystokinin antagonists II. Lipophilicity studies on 2-methyl-4-oxo-3H-quinazoline-3-alkyl-carboxylic acid derivatives

János Almási, Krisztina Takács-Novák, József Kökösi, József Vámos

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

The lipophilicity of 17 newly synthesized potential NMDA and cholecystokinin antagonist 2-methyl-4-oxo-3H-quinazoline-3-alkyl-carboxylic acid derivatives has been investigated. The apparent partition coefficients of two amphoteric compounds of overlapping protonation (Q1 and Q2) were determined by shake-flask method and converted into true logP values using the protonation microconstants. The difference between their lipophilicity expressed with the true partition coefficients was less, than it could be expected from the 2D structures and was explained with conformational preferences and formation of intramolecular interactions. Out of the other 15 monoprotic quinazolone compounds the lipophilicity of ten molecules (Q8-Q17, experimental set) was determined by TLC method with the help of a calibration set consisting of 12 standard molecules, five quinazolones (Q3-Q7) and seven pyrido[1,2-a]pyrimidines (PP1-PP7). In order to justify the suitability of pyrido-pyrimidines as standards for the chromatographic logP determination of quinazolones, first Q3-Q7 were examined by TLC and HPLC using PP1-PP7 for calibration. Data showed good agreement of results obtained by shake-flask and two different chromatographic methods indicating the similar chromatographic behavior of the two bicyclic systems and the relevance of PP1-PP7 to extend the calibration set of quinazolones. The obtained logP values proved mostly the expected structure-activity relationships. Some findings, however, have revealed specific partition behavior of the compounds providing useful information in the estimation of their pharmacokinetics, and these are discussed in the paper. Copyright (C) 1999 Elsevier Science B.V.

Original languageEnglish
Pages (from-to)13-22
Number of pages10
JournalInternational Journal of Pharmaceutics
Volume180
Issue number1
DOIs
Publication statusPublished - Mar 25 1999

Keywords

  • Lipophilicity
  • Quinazolones
  • TLC log P determination
  • True partition coefficient

ASJC Scopus subject areas

  • Pharmaceutical Science

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