INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY
WORLD HEALTH ORGANIZATION
TOXICOLOGICAL EVALUATION OF SOME
FOOD COLOURS, EMULSIFIERS, STABILIZERS,
ANTI-CAKING AGENTS AND CERTAIN
FAO Nutrition Meetings Report Series
No. 46A WHO/FOOD ADD/70.36
The content of this document is the result of the deliberations of the
Joint FAO/WHO Expert Committee on Food Additives which met in Rome,
27 May - 4 June 19691
Food and Agriculture Organization of the United Nations
World Health Organization
1 Thirteenth report of the Joint FAO/WHO Expert Committee on Food
Additives, FAO Nutrition Meetings Report Series, in press;
Wld Hlth Org. techn. Rep. Ser., in press.
Some silicone fluids may contain five per cent. of silica.
No data available.
Animal Route LD100 Reference
Rat s.c. > 5 000 Frazer et al., 1959
" > 5 000 "
i.m. > 5 000 "
" i.p. > 5 000 "
Rabbit s.c. > 5 000 "
" i.m. > 5 000 "
" i.p. > 5 000 "
Parentedal administration produced no significant gross or
histopathological abnormalities nor was any silicate found in the
urine of rats or rabbits (Frazer, 1959). Transient conjunctival
irritation has been noted both in rabbits and man for 24-48 hours
after contact (Child et al., 1951).
The data on acute toxicity vary with the viscosity and are generally
i.p. rat > 10 ml/kg body-weight (Rowe et al., 1948). Only
hexamethyldisiloxane and dodecamethylpentasiloxane appeared to be
toxic in acute tests and irritant on intradermal or subcutaneous
application to rabbits. Twenty percutaneous applications of all
silicone fluids for one month produced no adverse effects. (Rowe et
Rat. Four groups of five female rats each were fed diets containing
0 per cent, 0.1 per cent. silicone for three months. No adverse
effects were noted on general condition, body-weight, growth rate,
blood urea levels and organ weights. The histopathology of major
organs was normal (Child et al., 1951).
Groups of five female adult rats received 20 doses of 0, 1.0, 2.0,
5.0, 10.0 and 20.0 g/kg body-weight of silicone fluid (350 cSt) over
28 days without deleterious effects on growth, haematology, organ
weights and histopathology (Rowe et al., 1948). Silicone fluids of
viscosity 50, 350, 1000, 10 000, 60 000 cSt were fed for 90 days to
five groups of 10 male and 10 female rats at a level of one per cent.
in their diet. Twenty males and 20 females were controls. No
significant adverse effects were noted on mortality and food
consumption, body-weight, haematological indices, organ weights and
histopathology (MacDonald et al., 1960).
Groups of five male and five females rats were fed a diet containing
one per cent. silicone fluids of viscosity 50 and 350 cSt for one
year. Controls consisted of 10 male and 10 female rats. No adverse
effects were noted upon body-weight, haematology blood urea, nitrogen,
SGPT, cholesterol, serum alkaline phosphatase, urinalysis, organ
weights. Histological findings in major organs were normal (Carson et
A group of 10 rats (five male and five female) was fed a mixture (96
per cent. liquid dimethylpolysiloxane and four per cent. silica
aerogel) in the diet at a level of one per cent. for one year. Ten
male and 10 female rats served as control. No significant differences
were found between the test and the control animals in growth,
body-weight, haematology, blond urea, urine analysis, serum glutamic
pyruvic transaminase activity, organ weight (10 organs) and
histopathology (13 organs) (Carson et al., 1961).
Three groups of five males and five female rats were maintained for
approximately 260 days on diets containing 0.0 per cent., 0.5 per
cent., and two per cent. of a silicone emulsion consisting of 50 per
cent Antifoam A (silicon with silica) with two per cent.
pentaerythritol distearate as the emulsifying agent. No adverse
effects were noted on body-weight and organ weights. Blood remained
normal and no abnormal amounts of protein were seen in the urine.
Histology of major organs was normal. No effects were seen on
reproduction as measured by mating to produce and wean single sets of
offspring in each group (Frodsham, 1956).
Rabbit. In a similar experiment (see Carson, S., 1968) the same
mixture was fed to a group of six rabbits (three male and three
female) at a level of one per cent. in the diet for eight months. Six
male and six female rabbits served as control. No significant
differences were found between the test and the control animals in any
of the parameters listed in the rat study (Carson, 1968).
Groups of three male and three female rabbits were fed diets
containing one per cent. silicone fluids of viscosity 50 and 350 cSt
for eight months, Controls consisted of six male and six female
rabbits. No adverse effects were noted upon body-weight, haematology,
blood urea nitrogen, SGPT, cholesterol, serum alkaline phosphatase,
urinalysis, organ weights. Histological findings on major organs were
normal (Carson et al., 1966).
Dog. Groups of two adult dogs each were fed doses of 0, 300, 1000 or
3000 mg/kg body-weight silicone fluid five days each week for six
months. Apart from moist and frequent loose stools in test dogs no
abnormal effect on body-weight was noted. Small amounts of silicone
could be recovered from the faeces of the group fed 3000 mg/kg
body-weight. Haematology and urinalysis gave no abnormal findings.
Gross and histopathology revealed nothing abnormal. The liver of all
dogs fed silicone fluid but not of controls presented brown/black
deposits of iron-free bile in the Kupffer cells and parenchyma, the
quantities being directly related to the silicone dose administered,
similar deposits were also found in the interlobular bile ducts of
dogs fed the highest dose. The significance of these observations
remains unexplained (Child et al., 1951).
Rat. Groups of 25 male and 25 female rats were kept on a diet
containing 0 per cent. or 0.3 per cent. silicone fluid for two years.
There was no difference between tests and controls regarding
appearance, growth, survival or morbidity, haematology blood urea,
liver lipids, organ weights, macroscopic and microscopic pathology
(Rowe, et al., 1950). In another study three groups of 30 female and
10 male rats were fed a diet containing 0 per cent., 0.01 per cent.
and 0.1 per cent. silicone fluid and observed for two years. Two
further generations were reared and fed the same diets. The F1
generation was autopsied at 28 weeks, the F2 generation at 25 weeks.
There were no consistent adverse effects as regards body-weights,
fertility rates, mean litter size, survival, organ weights, gross and
histopathology. The consistent slight weight increase of the small gut
was not statistically significant. No silica was found in the gut wall
or any undue rise in other organs. Tumoric incidence was not abnormal.
Liver function tests, urinalysis, fat absorption, renal function tests
and haematology were not remarkable for F1 and F2 tests and
controls (Frazer, 1959).
Two groups of 10 weanling rats were kept on a diet containing 0 per
cent. and 0.1 per cent. silicone fluid for two years, There was no
consistent adverse effects as regards body-weight, behaviour, and
histopathology (Gloxhubor u. Hecht, 1955).
Studies have been carried out on silicone fluids with and without the
addition of silica. The presence of silica did not raise any
toxicological problems nor did it affect the results of the
experiments in a significant way. No bio-chemical studies are
available. Short-term studies have been carried out in several
species, including one study on an emulsion of dimethylpolysiloxane,
but only one adequate long-term study of dimethylpolysiloxane fluid
has been carried out in the rat. None of them has revealed any
Dimethylpolysiloxane fluid with or without silicon dioxide
Level causing no significant toxicological effect in the rat
0.1 per cent. (= 1 000 ppm) in the diet equivalent to 50 mg/kg body
Estimate of acceptable daily intake for man
Temporary acceptance 0 - 0.25
Further work required by June 1974
Metabolic studies in several species
Carson, S., Weinberg, M. S. & Oser, B. L. (1966) Proceedings of the
Scientific Section of the Toilet Goods Association, No. 45, 8-19
Child, G. P., Paquin, H. O., jr & Deichmann, W. B. (1951) Arch.
industr. Hyg., 3, 479
Frazer, A. C. (1959) Unpublished report dated November
Frodsham, J. (1956) Unpublished report No. 1HR/63, Imperial Chemical
Industries Ltd., Industrial Hygiene Research Laboratories
Gloxhuber, C. & Hecht, G. (1955) Arzneimittel, Forsch, 5, 10
MacDonald, W. E., Lainer, G. E. & Deichmann, W. B. (1960) Arch.
industr. Hyg., 21, 514
Rowe, V. K., Spencer, H. C. & Bass, S. L. (1948) J. industr. Hyg.,
Rowe, V. K. Spencer, H. C. & Bass, S. L. (1950) Arch. industr.
Hyg., 1, 539