Table 1

Chemical structures, milk and plasma fractionation data and milk/plasma partioning ratios for three nitrofuran drugs

PlasmaMilkRatio of Skim Milk to Whole MilkPredicted Milk/Plasma RatioObserved Milk/Plasma RatioRatio of Observed to Predicted
Un-ionizedUnboundUn-ionizedUnbound
Nitrofurantoin
0.390.430.610.741.190.3123.1∼75
Acidic (pKa = 7.2)
Solubility H2O = 190 μg/ml
Furazolidone
00.5600.481.210.971∼1
Neutral
Solubility H2O = 40 μg/ml
Furaltadone
10.8610.561.111.43.49∼2.5
Basic (pKa = 5.0)
Solubility H2O = 753 μg/ml