View Full Table | Close Full ViewTable 1.

Chemical structures and physicochemical properties of difloxacin and sarafloxacin.

 
Substance Chemical Abstracts Service no. Structure Formula pKa Kow
Difloxacin 98106–17–3 C21H19F2N3O3 pKa1: 5.7–6.1§
pKa2: 7.2–7.6§
0.89¶
Sarafloxacin 98105–99–8 C20H17F2N3O3 pKa1: 5.6#pKa2: 8.2# NA††
Acid dissociation constant.
Octanol-water partition coefficient.
§Taken from Ross and Riley (1990) and Barron et al. (2000).
Taken from Ross et al. (1992).
#Taken from Barron et al. (2000).
††Data not available.



View Full Table | Close Full ViewTable 2.

Soil dissipation half-life of difloxacin and sarafloxacin in the easily extractable and the accelerated solvent-extractable fraction in the laboratory trial and in the mesocosm trial and the field trial.

 
Trial Difloxacin
Sarafloxacin
Easily extractable fraction† Solvent-extractable fraction† Easily extractable fraction† Solvent-extractable fraction†
d
Lab incubation NS‡ 290* (190–580)§ n.d.¶ 2.7*,# (1.8–4.6)
Mesocosm trial
 Bulk soil n.d. NS n.d. NS
 Rhizosphere soil n.d. 82** (65–110) n.d. NS
Field trial
 Bulk soil NS 220** (170–320) n.d. n.d.
 Rhizosphere soil NS 69* (51–110) n.d. n.d.
*Parameter estimation of the underlying dissipation model significant at p < 0.1.
**Parameter estimation of the underlying dissipation model significant at p < 0.05.
Determined with the exponential dissipation model unless otherwise stated.
Curve fitting not significant.
§The uncertainty range of the dissipation half-life (determined from the fitted dissipation rate constant ± SE) is given in parentheses.
Not determined because of few data points.
#Exponential dissipation model plus constant.