Sodium methanolate - ipcs inchem

OECD SIDS
METHANOLATES
Due to the high alkalinity and corrosive nature of potassium methanolate and sodium and potassium
hydroxide no acute dermal studies were performed with these substances.
Due to the severe corrosivity sodium and potassium methanolate it is very unlikely that dermal
exposure of humans to sodium or potassium methanolate would lead to an uptake of methanol that
would be sufficiently high to cause acute methanol toxicity.
Oral
An aqueous solution of sodium methanolate (10 to 20 %) was tested for its acute toxicity according
to OECD guideline 401 and GLP in male and female Sprague-Dawley rats. The LD 50 was
1687 mg/kg bw. Animals of all dose groups showed symptoms of hunched posture lethargy and
decreased respiration rate. Macroscopic findings at necropsy in animals that died during the study
included red lungs pale, dark or patchy pale discoloration of the liver and at doses from 1587 mg/kg
bw severe hemorrhage and rugae of the glandular gastric epithelium as well as occasional adherence
of the stomach to the liver. In animals killed at termination occasional white foci in the nonglandular
stomach and adherence of the stomach to the liver was also observed (Degussa, 1988a).
Sodium methanolate was administered as a 2.15 to 10 % aqueous solution (volume administered
10 ml/kg) to male and female Sprague-Dawley rats by gavage at dose levels between 215 and
1000 mg/kg bw. All animals of the 1000 mg/kg dose group died while animals dosed up to
681 mg/kg bw survived. Clinical symptoms of dyspnea and apathy were observed in all dose
groups, at 316 mg/kg bw yellow discoloration of the urine was observed and disturbances of posture
and gait were observed from 681 mg/kg bw. Macroscopic findings were only observed in the
animals that died during the study and included dilatation and discoloration of the right heart, acute
congestive hyperemia, atonic stomach and intestines, fluid stomach and intestinal content and
diffuse reddening and vascular injection of the forestomach. The study was well documented, but
non-GLP (BASF AG, 1978b).
As both studies mentioned above were performed with aqueous solutions of sodium methanolate, in
fact the hydrolysis products have been tested.
Two other studies tested the acute oral toxicity to rats of suspensions of solid sodium methanolate
in non-aqueous solutions. An LD 50 value of 800 mg/kg bw was reported in a study using Lutrol as a
solvent. No characteristic symptoms were observed in this study. Macroscopic findings were only
reported in the animals that died during the study and included acute dilatation of the right heart and
congestive hyperemia as well as ulcerating gastritis, bleeding in the forestomach, thickened walls of
the glandular stomach, adhesions between stomach and liver atonic intestine with bloody content,
hydrothorax and partly blood colored ascites. (BASF AG, 1979b). This study is a well documented
non-GLP study.
In another well documented non-GLP study a suspension of sodium methanolate in corn oil was
administered to male and female Sprague Dawley rats. In this study an LD 50 of 2037 mg/kg bw was
obtained. Labored breathing, weakness, wet and stained perianal area as well as chromodacryorrhea
and ruffled fur were observed in all animals. Macroscopic findings were not reported in the
reference. (Dupont de Nemours, 1982).
The difference between the two studies in non-aqueous solvents is probably due to their different
lipophilicity. Lutrol is hydrophilic and readily dissolved in the aqueous gastric fluid liberating the
dispersed test substance that will hydrolyze immediately delivering the hydrolysis products at a
relative high concentration to the stomach tissue. This leads to the relative severe signs of irritation
and corrosivity. The lipophilic corn oil on the other hand can be expected to release the test
substance more slowly from the administered bolus leading to a lower tissue concentration of the
hydrolysis products and less damage to the gastric mucosa.
UNEP PUBLICATIONS 19