J. Barbosa et al., DISSOCIATION-CONSTANTS AND PREFERENTIAL SOLVATION OF FLUOROQUINOLONESIN HYDROORGANIC MIXTURES USED IN LC, International journal of pharmaceutics, 149(2), 1997, pp. 213-225
The examination of the protonation equilibria of fluoroquinolones is e
ssential in order to understand their antibacterial activity. The pK v
alues of three representative and widely used fluoroquinolones such as
flumequine, norfloxacin and fleroxacin in some acetonitrile-water mix
tures were obtained and correlated with the Taft and Kamlet solvatochr
omic parameters, pi, alpha and beta. The pK values of antimicrobial q
uinolones in any acetonitrile-water mixture up to 70% (w/w) can be cal
culated from the relationships found and the most important solvent pr
operties that affect electrolyte dissociation can also be evaluated. M
oreover, variations in the pK values obtained over the whole compositi
on range studied was explained by means of preferential solvation of e
lectrolites in acetonitrile-water mixtures. (C) 1997 Elsevier Science
B.V.