A comparative kinetics study of monochloramine and hypochlorous acid in rat.

The problem of trihalomethane formation now exists with the use of chlorine (technically, a mixture of HOCl and OCl-, depending on pH) as a disinfectant in drinking water. Monochloramine (NH2Cl) may be considered as an alternative to HOCl as a disinfectant in public water supplies. This study was conducted to compare the kinetics of NH2(36)Cl with HO36Cl in rats. The peak plasma levels of 36Cl occurred at 8 and 2 h for NH2(36)Cl and and HO36Cl, respectively. The distribution of NH2(36)Cl and HO36Cl was highest in plasma, while the lowest activity was observed in the fat. The half-life for 36Cl absorption was 2.49 and 2.16 h, while the elimination from plasma was 38.8 and 44.1 h after oral NH2(36)Cl and HO36Cl treatment, respectively. Urinary excretion accounted for most of the 36Cl eliminated in both treatments.