LINEAR ALKYLBENZENE SULFONATE (LAS) - UNEP Chemicals

OECD SIDS LINEAR ALKYLBENZENE SULFONATE (LAS)
feces, respectively, during 5 days, mostly during the first 24 hours. After
single oral doses of 30, 150 and 300 mg/kg, peak plasma concentrations (at 4
hours in all cases) were very similar, with levels of 34, 41 and 36 µg/mL,
respectively. Concentrations declined during the period of 6-24 hours, with a
biological half life of about 6.5 hours. After single subcutaneous doses of
0.1, 0.5 and 1 mg/kg, peak plasma concentrations increased almost
proportionately, with levels of 0.16, 0.72 and 1.13 µg/mL, respectively.
During the 120 hours after single oral (30 mg/kg) or subcutaneous doses (1
mg/kg) the average rate of excretion was between 63 and 74% in the urine
and between 9 and 26% in the feces.
During seven consecutive daily oral (30 mg/kg/day) or subcutaneous (1
mg/kg/day) doses, there was no accumulation of radioactivity in plasma.
Mean peak concentrations and biological half-lives were similar after the first
and seventh doses. Two hours after the last dose, the highest radioactivity
was observed in the stomach. Radioactivity was also observed in the
intestinal tract, kidneys, liver, lung, pancreas, adrenals and pituitary. At 24
hours, concentrations were highest in the intestinal tract, probably indicating
biliary excretion. Since the concentrations in the tissues in general were
lower than in plasma, no specific accumulation of LAS occurred. When 14 C-
LAS was injected into the skin, most of the radioactivity remained at the site
of injection. No localization of radioactivity in any tissue occurred. No
unchanged LAS was detected in urine samples after oral or subcutaneous
doses (either single or repeated).
Five metabolites were excreted but they were not identified. Incubations
with beta-glucuronidase/sulfatase did not affect the metabolites, indicating
that the metabolites were probably not present as the corresponding
conjugates.
Test substance: Alkyl benzene sulfonate, sodium salt; mean molecular weight 349 (supplied
by the Japan Soap and Detergent Association)
Reference: Cresswell, D.G., Baldock, G.A., Chasseaud, L.F. and Hawkins, D.R. 1978.
Toxicological studies of linear alkylbenzene sulfonate (LAS) in rhesus
monkeys: (II) the disposition of [ 14 C] LAS after oral or subcutaneous
administration. Toxicology 11:5-17.
Reliability: 2 Valid with restrictions
(e)
Type: Toxicokinetics
Results: Rats were dosed orally with 14 C-Na-LAS and radioactivity was detected 0.25
hr after administration, reaching a maximum at 2 hrs. The biologically half
lives were calculated to be 10.9 hrs. The distribution was high in the
digestive tract and in the bladder at 4 hours after administration.
Concentrations were also high in the liver, kidney, testis, spleen and lung.
168 hours after the administration, the rates of excreted radioactivity were
47% in the urine and 50% in the faeces
Remarks: Information as cited in the IUCLID Data Sheet and the IPCS document.
Reference: 1) European Commission. 2000a. Benzenesulfonic acid, C10-13-alkyl derivs.,
sodium salts. Year 2000 CD-ROM edition.
2) Sunakawa, T., Ikida, Y. and Okamoto, K. 1979. Absorption, distribution,
metabolism, and excretion of linear alkylbenzene sulfonate in rats. J. Jpn. Oil
Chem. Soc. 39:59-68 (in Japanese); cited in: IPCS (1996); Environmental
Health Criteria 169: Linear Alkylbenzene Sulfonates (LAS) and Related
Compounds. WHO, Geneva, Switzerland.
Reliability: 4 This study is assigned a reliability score of 4 because the original report
was not available for review. However, the study was evaluated by IPCS
prior to inclusion in their criteria document.
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