Safety evaluation of certain food additives - ipcs inchem

CALCIUM LIGNOSULFONATE (40–65) 19
the test substance or resulted from non-aqueous hydrogen. Hydrogen tracer from
tritiated water is present in non-aqueous hydrogen (mainly protein and
carbohydrates) as a result of exchange reactions between molecules and water
(with and without enzymes). The reported tritium levels of 0.5–2% (Sheng &
Huggins, 1979) and 2–4% (Ellis, 2000) in non-aqueous hydrogen (resulting from
the presence of tritiated water) would possibly explain the observed levels of
radioactivity in molecules of higher weight in plasma (1%) and urine (3.2% at 24 h).
It should be noted that many soluble proteins have a molecular weight near to the
average molecular weight of the test substance and could therefore not be
separated under the chromatographic conditions applied.
In summary, after 48 h, only 0.8% of the radioactivity administered as
3 H-labelled calcium lignosulfonate (40–65) is found in urine (0.05%), liver (0.08%),
blood (0.01%) and the remaining carcass (0.66%). The study demonstrates that
calcium lignosulfonate (40–65) absorption after oral administration is very low, and
systemic exposure is below 1%.
2.1.2 Biotransformation
Since calcium lignosulfonate (40–65) absorption is negligible, potential in
vivo metabolic transformation of the additive was not studied.
2.2 Toxicological studies
2.2.1 Short-term studies of toxicity
In a 28-day feeding study compliant with Organisation for Economic Cooperation
and Development (OECD) guidelines and Good Laboratory Practice
(GLP), calcium lignosulfonate (40–65) was administered to Wistar rats (Weber &
Ramesh, 2005). Four groups, each consisting of six animals per sex, received the
test substance at target dose levels of 0, 500, 1500 or 4000 mg/kg bw per day via
the diet. Actually achieved doses were 0, 413, 1301 and 3495 mg/kg bw per day in
males and 0, 453, 1345 and 3609 mg/kg bw per day in females. The diet was
prepared once weekly and offered to the animals ad libitum. Dietary concentrations
were adjusted each week based on body weights and food consumption. Analytical
results showed that calcium lignosulfonate (40–65) was stable in the diet and
distributed homogeneously. Animals were observed for morbidity and mortality
twice daily and for clinical signs once daily. Detailed clinical examination, body
weights and food consumption were determined weekly. An ophthalmoscopic
examination was carried out before treatment and near scheduled termination.
Blood smears for differential leukocyte count were obtained from the tail on the day
prior to sacrifice; blood for clinical chemistry was obtained at scheduled termination
from the abdominal aorta after overnight fasting. All animals were subjected to a
detailed gross necropsy. Liver, kidneys, adrenals, gonads, epididymides, thymus,
spleen, brain and heart were weighed. These tissues plus other tissues as specified
by OECD guidelines were preserved for histological evaluation. Tissues of the
control and high-dose groups were subjected to histopathological examination. The
recta of low-and mid-dose males were also examined.