Multiwavelength spectrophotometric determination of acid dissociation constants part V: microconstants and tautomeric ratios of diprotic amphoteric drugs.

@article{TakcsNovk2000MultiwavelengthSD,
  title={Multiwavelength spectrophotometric determination of acid dissociation constants part V: microconstants and tautomeric ratios of diprotic amphoteric drugs.},
  author={Krisztina Tak{\'a}cs-Nov{\'a}k and Kin Yip Tam},
  journal={Journal of pharmaceutical and biomedical analysis},
  year={2000},
  volume={21 6},
  pages={1171-82}
}
The acid-base equilibria of several diprotic amphoteric drugs, namely, niflumic acid, norfloxacin, piroxicam, pyridoxine and 2-methyl-4-oxo-3H-quinazoline-3-acetic acid have been characterized in terms of microconstants and tautomeric ratios. A multiwavelength spectrophotometric (WApH) titration method for determination of acid dissociation constants (pKa values) of ionizable compounds developed previously was applied for this purpose. Microspeciation was investigated by three approaches: (1… CONTINUE READING