TOXICOLOGICAL EVALUATION OF CERTAIN FOOD ADDITIVES
WHO FOOD ADDITIVES SERIES 10
The evaluations contained in this document were prepared by the
Joint FAO/WHO Expert Committee on Food Additives*
Rome, 21-29 April 1976
Food and Agriculture Organization of the United Nations
World Health Organization
*Twentieth Report of the Joint FAO/WHO Expert Committee on Food
Additives, Geneva, 1976, WHO Technical Report Series No. 599, FAO Food
and Nutrition Series No. 1.
DIETHYLENE GLYCOL MONOETHYL ETHER
Biological Data
BIOCHEMICAL ASPECTS
Diethylene glycol monoethyl ether administered orally or
subcutaneously in doses of 3-5 ml/kg BW to rabbits produced an
increased urinary excretion of glucuronic acid. This increase could
account for only 0.8-2.3% of the dose administered. (Fellows et al.,
1946)
TOXICOLOGICAL STUDIES
Acute Toxicity
LD50
Animal Route (ml/kg body-weight) Reference
Rat oral 5.5-9.7 Hanzlik et al., 1947a
s.c. 6.0 "
Mouse oral 6.6 Lang et al., 1939
s.c. 2.5-6.0 Hanzlik et al., 1947a
i.p. <2.0 "
Guinea, pig oral 3.7-5.0 Lang et al., 1939
Rabbit i.v. 2.5 "
Dog i.v. 3.0 "
Cat s.c. 1.0-2.0 Lehmann and Fury, 1943
i.v. 4.2 Lang et al., 1939
No abnormalities were obvious below a dosage level of 1 ml/kg by
any route. Ataxia with initially increased and later decreased
respiratory rate occurred with 2-2.5 ml/kg while higher dosage levels
led to central nervous depression and coma followed by recovery or
death.
SHORT-TERM STUDIES
Mouse
Groups of 20 male and 20 female mice were fed on diets containing
0, 0.2, 0.6, 1.8 or 5.4% diethylene glycol monoethyl ether (containing
less than 0.4% ethylene glycol) for 90 days. Half of the 5.4% group
died between the 5-12th weeks and of these 6 showed hydropic
degeneration of the kidney. The growth rate was reduced and anaemia
was found in males at the highest dosage level. Serum transaminase and
urea levels were unaffected by treatment. The relative body-weight was
increased in both sexes receiving the 5.4% diet and in males fed on
1.8% diet. In females receiving the highest dosage level the relative
heart and liver weights were greater than in controls. Centrilobular
hepatocyte enlargement was found at the 5.4 and 1.8% dietary levels.
Renal tubular cell enlargement with nuclear pyknosis occurred in
animals at the 5.4% dietary level. Areas of tubular degeneration and
atrophy were seen in all groups but they appeared with greater
frequency at the top feeding level. No oxalate crystals were seen in
the kidneys or bladder. The no-effect level was 0.6%, equivalent to an
intake of 850-1000 mg/kg/day. (Gaunt et al., 1968)
Rat
Groups of 12 male and 12 female rats were fed for 90 days on
diets containing 0, 0.25, 1.0 or 5.0% diethylene glycol monoethyl
ether contaminated by 0.64% ethylene glycol. The condition and health
of the animals remained good but 1 male on the 5% diet died after 23
days following a period of weight loss. No abnormalities were found on
haematological examination. Urinary glutamic oxalacetic transaminase
activity was significantly increased and the relative kidney weight
raised in both sexes and the relative testes weight raised in males of
the 5% group. Tubular dilatation with inflammatory cell infiltration
was present in all groups but was accentuated in the 5% group.
Hydropic degeneration was seen in 2 males and 1 female and slight to
moderate fatty infiltration in most animals was also found in this
group. The no-effect level was 1% in the diet, equivalent to 800 mg/kg
BW/day. (Hall et al., 1966)
Groups of 15 male and 15 female rats were fed on diets containing
0, 0.5 or 5.0% diethylene glycol monoethyl ether (containing less than
0.4% ethylene glycol) for 90 days. No animals died. The growth rate
and food intake were reduced and slight anaemia was seen in females
after 6 weeks and in males at the end of the study at the highest
dosage level. Serum urea and transaminase levels were unaffected by
treatment. The relative weight of kidneys was increased in the 5%
group and cells of the proximal tubular cells were grossly enlarged
with pyknotic nuclei. No oxalate crystals were found in the kidneys
or bladder. The no-effect level was 0.5% in the diet, equivalent to
250 mg/kg/day. (Gaunt et al., 1968)
Ferret
Groups of 2 or 3 male ferrets were fed on diet providing
0, 0.5, 1.0, 2.0 or 3.0 ml diethylene glycol monoethyl ether/kg
body-weight/day for 9 months. The sample of solvent contained less
than 0.4% ethylene glycol. The body-weights of the two highest dosage
levels tended to be lower than those of controls and their food intake
was also diminished. No abnormal constituents were found in urine. The
water intake of all treatment groups was greater than controls during
the period of measurement (first seven weeks). The concentrating power
of the kidney was decreased consistently at the two highest dosage
levels. However at necropsy organ weights were not changed by
treatment and no abnormal gross or histopathological abnormalities
were detected. The no-effect level was 0.5 ml/kg BW. (Butterworth et
al., 1975)
Pig
Groups of 3 male and 3 female pigs were administered diethylene
glycol monoethyl ether in their diet for 90 days. Initially the daily
intake was 0, 167, 500 or 1500 mg/kg BW/day but the top dose was
reduced to 1000 mg/kg BW/day after 3 weeks since 2 animals had to be
killed in extremis after 2 and another after 3 weeks. These pigs
became lethargic and comatose and autopsy showed subcutaneous and
pulmonary oedema and pleural and peritoneal effusions. The livers
were of a yellowish colour and they were enlarged, the cut surfaces
showing a pale cortex with petechial and medullary congestion.
Calculi were found in the urinary tract. Proteinurea with casts also
occurred. Serum urea was elevated to above 100 mg% and histological
examination showed hydropic degeneration and tubular desquamation with
glomerular atrophy. Livers showed extensive hydropic degeneration.
There was slight anaemia in males receiving 1000 mg/kg/day for the
full 90 days and more severe anaemia in those that died. Serum urea
and transaminase levels were normal in all animals killed at the end
of the investigation. The kidney weight was elevated in animals
receiving the highest dosage level. Hepatocytes of centrilobular and
midzonal areas were grossly enlarged with pyknotic nuclei and fatty
infiltration occurred at the top dosage level and in one female
receiving 500 mg/kg diet. Most of the renal cortex was affected by
extensive areas of tubular hydropic degeneration at the highest
dosage level but this was less marked at the 500 mg/kg level. Other
changes at the 1000 mg/kg level were consistent with uraemia resulting
from renal failure. No oxalate crystals were seen in the kidneys or
bladder. The no-effect level was 167 mg/kg/day. (Gaunt et al., 1968)
LONG-TERM STUDIES
Mouse
Groups of 10 male and 10 female mice were fed on control diet or
diet containing 5% diethylene glycol monoethyl ether (purity: less
than 0.2% ethylene glycol). This provided males with 7.5 and females
with 6.0 ml/kg BW/day. The body-weights were reduced in males between
the 2-6th months but were similar to controls at other times. Body-
weight was continuously lower than controls in females. Approximately
40% of test and control females were alive at 12 months while males
survived longer, the last test male dying at 18 and control at 21
months approximately. Only one of 30 animals receiving diethylene
glycol monoethyl ether (pure or containing 1% ethylene glycol) showed
hydropic degenerative change in the kidneys. (Hanzlik et al., 1947b)
Rat
A group of 8 female and 12 male rats were fed on a diet
containing 2.16% diethylene glycol monoethyl ether for up to 2 years.
A similar group of litter mates received control diet. Food and water
were offered ad lib. No significant decrease in growth rate occurred
in the test group and the mortality rate was unaffected; however, the
number of animals surviving for 2 years was not stated. Only animals
surviving the longest received full pathological examination but the
number examined was not stated. In the test group there was an
increased incidence of testicular atrophy with interstitial oedema,
centrilobular or diffuse atrophy of the liver with bile duct
proliferation and fatty degeneration and an oxalate concentration was
found in the kidney of one animal. (Morris et al., 1942)
A group of 10 male and 5 female rats were administered diethylene
glycol monoethyl ether (purity: less than 0.2% ethylene glycol) as a
1% solution in drinking water. Thirteen male and 8 female control rats
received uncontaminated water; both received diet and drinking fluid
ad lib. The intake of monoethylene glycol monoethyl ether was
approximately 1.3 ml/kg BW/day in male and 1.5 ml/kg BW/day in female
animals. No significant differences were found in growth rate or in
food or fluid intakes. After 12 months approximately 8 test and 4
control animals remained alive. No gross or microscopic abnormalities
were found in the small number of animals examined. (Hanzlik et al.,
1947b)
Groups of 8 male and 8 female Wistar rats received drinking water
incorporating diethylene glycol monoethyl ether containing either
29.5% ethylene glycol or less than 0.2% ethylene glycol. Groups
received the equivalent of 0, 10, 40, 190 or 950 mg of the diethylene
glycol monoethyl ether mixture/kg BW/day or 0, 9, 39, 200 or 920 mg of
the purer substance/kg BW/day for up to 757 days. Feed and drinking
fluids were available ad lib.
Animals were allowed to produce offspring to form a first
generation and a second generation was produced from these. However,
the length of the period of treatment of the offspring was not given.
The life span of animals receiving 950 mg of the mixture/kg
BW/day was significantly shortened compared with controls but other
groups were unaffected. Growth was reduced compared with controls in
animals of the parent generation receiving 950 and 190 mg mixture/kg
BW/day or 920 mg purer diethylene glycol monoethyl ether/kg BW/day but
the effect on growth in other groups and other generations was
probably not of significance. No adverse effects were found on
haematological examination, and blood urea and glucose and serum
proteins were unaffected by the treatments. No increase in oxalic or
oxaluric acids were found in the urine of test animals; although the
urine protein concentration was raised in the 950 mg and 920 mg/kg
groups.
The tumours found were typical of elderly rats and the overall
incidence (4.4%) was similar to other reported figures for the strain
of rat. However, the report does not allow a full assessment of the
incidence and types of tumours in each group. Bladder calculi were
found only in animals receiving the highest dosage level of the
mixture. Only the liver and kidney were examined microscopically in
all animals but a few more organs were examined in others. Epithelial
necrosis of the renal tubules and cloudy swelling of hepatic tissue
were the only adverse effects which could be attributable to
treatment and these were seen in animals receiving 950, 190 and
40 mg mixture/kg/day and 920 mg purer diethylene glycol monoethyl
ether/kg/day.
The "no adverse effect level" for diethylene glycol monoethyl
ether containing less than 0.2% ethylene glycol was 200 mg/kg/day.
(Smythe et al., 1944)
Comments
Several long-term tests on rats and mice have been reported. The
results indicate that the solvent has no effects other than those seen
in short-term tests in these species. However, the study carried out
in the pig was not of sufficient duration and it is possible that the
lesions would have occurred at a lower dosage level on longer-term
feeding. None of the long-term studies are reported fully enough to
demonstrate lack of carcinogenicity. Although one study suggests no
adverse effects, no adequate reproduction or teratogenicity studies
are available.
EVALUATION
No acceptable daily intake for men has been allocated.
Further work or information required before an ADI can be allocated
1. Studies on absorption, distribution, excretion and metabolism of
diethylene glycol monoethyl ether.
2. An adequate carcinogenicity study.
3. A 6-month study in the pig.
4. Studies on the effects in reproduction and possibly
teratogenicity.
REFERENCES
Butterworth, K. R., Gaunt, I. F. and Grasso, P. (1975) A nine month
toxicity study of diethylene glycol monoethyl ether in the
ferret. Unpublished report by the British Industrial Biological
Research Association
Fellows, J. K., Luduena, F. P. and Hanzlik, F. J. (1947) "Glucuronic
acid excretion after diethylene glycol monoethyl ether (carbitol)
and some other glycols", J. Pharmacol., 89, 210-213,
Gaunt, I. F., Colley, J., Grasso, P., Lansdown, A. B. G. and Gangolli,
S. D. (1968) Short-term Toxicity of Diethylene glycol monoethyl
ether in the Rat, Mouse and Pig, Food Cosmet. Toxicol., 6,
689-705
Hall, D. E., Lee, F. S., Austin, P. and Fairweather, F. A. (1966)
"Short-term feeding study with diethylene glycol monoethyl ether
in rats", Food Cosmetics Toxicology, 4, 263-268
Hanzlik, P. J. Luduena, F. P., Lawrence, W. S. and Hanzlik, H.
(1947a) Acute toxicity and general systemic actions of diethylene
glycol monoethyl ether (Carbitol), J. Ind. Hyg. Toxicol., 29,
190-195
Hanzlik, P. J., Lawrence, W. S. and Laquer, G. L. (1947b) "Comparative
chronic toxicity of diethylene glycol monoethyl ether (carbitol)
and some related glycols: results of continued drinking and
feeding", J. Ind. Hyg. Toxicol., 29, 233-241
Lang, E. P., Calvery, H. O., Morris, H. J. and Woodard, G. (1939) "The
toxicology of some glycols and derivatives", J. Ind. Hyg.
Toxicol., 21, 173
Lehmann, K. B. and Flury, F. (1943) Translated by King, E. and Smyth,
H. F., jr "Toxicology and hygiene of industrial solvents",
Williams and Wilkins, Baltimore, p. 378
Morris, H. J., Nelson, A. A. and Calvery, H. O. (1942) "Observations
on the chronic toxicities of propylene glycol, ethylene glycol,
diethylene glycol, ethylene glycol monoethyl ether and diethylene
glycol monoethyl ether", J. Pharmacol., 74, 266-273
Smythe, H. F., Carpenter, C. P. and Shaffer, C. B. (1944) "Two-Year
oral doses of Carbitol to rats". Unpublished report No. 7-31 by
the Mellon Institute of Industrial Research
See Also:
Toxicological Abbreviations
Diethylene glycol monoethyl ether (ICSC)
Diethylene glycol monoethyl ether (WHO Food Additives Series 30)
DIETHYLENE GLYCOL MONOETHYL ETHER (JECFA Evaluation)