Study of the teratogenic potential of FD & C Yellow No. 5 when given by gavage to rats

FD & C Yellow No. 5 (tartrazine) was given to Osborne-Mendel rats by gavage at dose levels of 0, 60, 100, 200, 400, 600 or 1000 mg/kg body weight/day on days 0–19 of gestation. No maternal or developmental toxicity was observed when the rats were killed on day 20. The mean daily food consumption for the entire period of gestation was significantly greater in the females given 1000 mg/kg body weight/day than in the controls, but maternal body-weight gain was not affected. No dose-related effects were observed in implantations, foetal viability or external foetal development. Foetal skeletal and visceral development was similar among foetuses from all groups. At the doses given, FD & C Yellow No. 5 was neither toxic nor teratogenic.     

Study of the teratogenic potential of FD & C yellow No. 5 when given in drinking-water.

FD & C Yellow No. 5 was available to pregnant Osborne-Mendel rats throughout gestation at dose levels of 0.05, 0.1, 0.2, 0.4 or 0.7% in solution in distilled drinking-water. Based on fluid consumption, the rats received 67.4, 131.8, 292.4, 567.9 and 1064.3 mg FD & C Yellow No. 5/kg body weight/day. Distilled water served as the control. No dose-related changes were seen in mean daily food consumption or maternal body-weight gain. Starting during the second trimester of gestation, fluid consumption was significantly greater in the rats given 0.7% FD & C Yellow No. 5 than in the controls. The females were killed on gestation day 20. No dose-related changes were seen in maternal clinical findings, implantations, foetal viability or foetal size (weight and length). No dose-related foetal terata were seen. Neither visceral development nor skeletal development (sternebral and other skeletal bones) was affected by the dye. The small numbers of statistically significant increases in skeletal variations in the 0.05 and 0.4% levels are considered random because they are not dose related.     

Lifetime toxicity/carcinogenicity study of FD & C Red No. 40 (allura red) in Sprague-Dawley rats

FD & C Red No. 40 was fed to Charles River CD (Sprague-Dawley) rats as a dietary admixture in a lifetime toxicity/carcinogenicity study. The study included a phase during which the colouring was administered to parental rats (30 of each sex per group) at concentrations of 0.0, 0.37, 1.39 and 5.19%, throughout the mating, gestation and lactation periods. The concurrent control group received the basal diet. After random selection of the first-generation rats, the lifetime phase was initiated using the same dietary concentrations with 50 rats of each sex per group. The maximum durations of exposure to the colouring were 118 and 121 for males and females, respectively. No compound-related adverse effects were observed, except for a reduction in body weight in high-dose females at the end of the study. The no-adverse-effect levels in this study were 5.19% (2829 mg/kg/day) for male rats, and 1.39% (901 mg/kg/day) for female rats.     

The teratogenic potential in rats and rabbits of D & C Yellow No. 8

The teratogenic potential of D & C Yellow No. 8, sodium fluorescein (C.I. No. 45350, CAS No. 518-47-8) was determined in rats and rabbits. An aqueous solution of the dye was administered by gavage to groups of 25 Charles River Sprague-Dawley rats at doses of 100, 500 and 1500 mg/kg on days 6-19 of gestation and to groups of 14 Dutch Belted rabbits at doses of 30, 100 and 250 mg/kg on days 6-27 of gestation. These doses did not result in evidence of maternal toxicity or adverse effects on foetal development.     

Evaluation of the potential teratogenicity of FD & C Blue No. 2 in rats and rabbits

Charles River CD rats (20 pregnant rats/group) received by gavage on days 6-15 of gestation 0.5% Methocel (controls, A, B and C), retinoic acid at 7.5 mg/kg/day or FD & C Blue No. 2 in doses of 25, 75 or 250 mg/kg/day. Pregnant Dutch belted rabbits (ten pregnant does/group) received by gavage on days 6-18 of gestation 0.5% Methocel (controls A, B and C), thalidomide at 150 mg/kg/day or FD & C Blue No. 2 in doses of 25, 75 or 250 mg/kg/day. All animals were observed twice daily during gestation for signs of toxicity. The animals were killed 1 day before term and appropriate maternal and foetal parameters were evaluated. There were no consistent, significant compound-related adverse effects on any of these parameters. Foetal malformations occurred in both positive control groups. Under the conditions of this study, FD & C Blue No. 2 did not exert any teratogenicity or other developmental toxicity in either rats or rabbits.     

Multigeneration study of FD & C Blue No. 2 in rats

In a three-generation reproduction study, groups of ten male and 20 female Charles River CD rats were fed FD & C Blue No. 2 at dietary levels providing intakes of 0.0, 2.5, 25, 75 and 250 mg/kg body weight/day. Slightly bluish-coloured fur was noted in rats at the 250-mg/kg/day dose level and bluish-green-coloured faeces were produced by rats in the 75- and 250-mg/kg/day groups. The gestation, viability and lactation indices of all litters were comparable for the control and treated groups. The fertility indices for female rats in the 2.5- and 25-mg/kg/day groups were significantly lower than those for control females in the case of the F2 litters. However, there was no reduction in the female fertility indices for the F2 litters at the two higher dosage levels, nor for the F1 and F3 litters at any dosage level. Although fertility indices were reduced for some groups of male rats in the F2b and F2c litters, these changes were not considered to be compound-related. Examination of the ovaries and uteri of all dams killed on day 19 of gestation of the F2c and F3c litters revealed no gross anatomical abnormalities. No unusual changes were observed in the stillborn pups or in pups dying during the study. There were no compound-related gross or microscopic pathological lesions in any of the F1 or F3a rats that were killed and necropsied, and no compound-related organ-weight variations were recorded in the F1 parental rats.     

Lifetime toxicity/carcinogenicity study of FD & C Red No. 3 (erythrosine) in rats

FD & C Red No. 3 was fed to Charles River CD rats as a dietary admixture in two long-term toxicity/carcinogenicity studies. The studies consisted of an in utero and an F1 phase. In the former, the compound was administered to five groups of the F0 generation rats (60 of each sex/group) at levels of 0.0, 0.0, 0.1, 0.5 or 1.0% ('original study') and 0.0 or 4.0% ('high-dose study'). The concurrent control groups received the basal diet. After random selection of the F1 animals, the long-term phase was initiated using the same dietary levels and 70 rats of each sex/group, including the three control groups. Rats were exposed for a maximum of 30 months. No compound-related effects were noted in the in utero phase. Mean body weights of the female F1 rats on 4.0% FD & C Red No. 3 (3029 mg/kg/body weight/day) were significantly lower than those of controls (P less than 0.01) throughout the study. Food consumption increased in all treated groups in a dose-related manner. There were no significant effects on the haematology, serum chemistry and urinalysis and no compound-related effects on survival. In male rats receiving 4.0% FD & C Red No. 3 (2464 mg/kg/day) thyroid weights were increased, with a mean weight of 92 mg compared to 44 mg for controls, and statistically significant increases in the incidence of thyroid follicular cell hypertrophy, hyperplasia and adenomas were recorded. A numerically increased incidence of thyroid follicular adenomas in female rats given 0.5, 1.0 or 4.0% FD & C Red No. 3 was not statistically significant. The no-observed-adverse-effect levels established in these studies were 0.5% (251 mg/kg/day) for male rats and 1.0% (641 mg/kg/day) for females.     

A study of the teratogenic potential of caffeine given by oral intubation to rats

A study was made to resolve questions about the fetotoxic and teratogenic potential of the alkaloid caffeine, 1,3,7-trimethylxanthine. Caffeine in aqueous solution was orally intubated to Osborne-Mendel rats as dose levels of 6, 12, 40, 80, or 125 mg/kg during Days 0–19 of gestation; 61 rats were randomly assigned to each dose level. Concurrent control rats were intubated with distilled water on the same days. Six females died at the highest caffeine dose level. The experimental animals gained less weight during gestation than did the controls. Food consumption decreased primarily during the first week of gestation. Two litters were totally resorbed at 80 mg/kg and four litters at 125 mg/kg. Resorptions increased at the dose levels 80 and 125 mg/kg. These were significant decreases in fetal weight and crown-rump lengths in both males and females at 80 and 125 mg/kg, and in female weight and crownrump length at 40 mg/kg. Ectrodactyly was seen only at the dose levels 80 and 125 mg/kg, along with assorted skeletal ossification problems such as misshapen centra, missing centra, reduced dorsal arch, reduced pubis, missing hind phalanges, reduced metacarpals, and reduced metatarsals. In addition, delayed ossification of the sternebrae was seen at all dose levels. No soft tissue variations appeared related to caffeine intake.     

Evaluation of the teratogenic potential of phosphamidon in mice by gavage

Phosphamidon, an organophosphate pesticide, is an established cholinesterase inhibitor. Alteration of tissue and plasma cholinesterase activity at a critical developmental period may influence cellular division and growth sufficiently to produce anatomically or functionally abnormal tissue or organ. The present study was, therefore, undertaken to evaluate the teratogenic potential of phosphamidon in pregnant Swiss albino mice, when administered at different gestational days during the period of organogenesis. The animals were sacrificed on day 18 of gestation for routine teratological examinations. It was observed that phosphamidon was more embryotoxic than teratogenic. Maximum effects were observed when administered on day 7 and day 13. Treatment on day 10 produced little effects. Repeated exposure during the organogenetic phase also produced significant adverse effects. This possibly indicates that phosphamidon is more embryotoxic during the post-implantation period (day 7) and during late organogenesis (day 13) as compared to the early organogenesis period (day 10).     

Carcinogenesis in rats by substituted dialkylnitrosamines given by gavage.

A number of nitrosamines that have been studied by administration to rats as solutions in drinking water have been examined by gavage administration of similar doses, for assessment of the role of pharmacokinetics in organ-specific carcinogenesis. Methylnitrosoethylamine was more effective as a liver carcinogen by gavage than in drinking water and gave rise to tumors of the lung and nasal mucosa by the former route, but not the latter. By gavage, methylnitroso-2-oxopropylamine and methylnitroso-2-hydroxypropylamine induced mainly tumors of the esophagus, as they did when given to rats in drinking water, but the potency was greater by gavage. At a higher dose rate (85 micromoles per week) methylnitrosohydroxypropylamine induced a high incidence of mesenchymal tumors of the kidney and lung tumors, in addition to esophageal tumors, but methylnitrosooxopropylamine did not. The tobacco-specific carcinogen NNK induced tumors of the liver, and to a lesser extent, of the lung and nasal mucosa when given by gavage to rats, as it did by other routes of administration. The similarly basic nitrosamine methylnitroso-N, N-dimethylaminoethylamine was equally potent, whether administered by gavage or in drinking water to rats, and gave rise only to tumors of the esophagus. The cyclic nitrosamine nitrosomorpholine was equally effective by gavage and in drinking water, but induced in rats more esophageal tumors by gavage in addition to a high incidence of liver tumors. Its 2-hydroxy derivative, a postulated metabolic intermediate of nitrosodiethanolamine, was a very much weaker carcinogen than either the latter or nitrosomorpholine, and induced low incidences of liver and lung tumors toward the end of the lifespan of the rats.     

Lifetime toxicity/carcinogenicity study of FD & C Red No. 3 (erythrosine) in mice

Charles River CD-1 mice were fed FD & C Red No. 3 in the diet at levels of 0.3, 1.0 and 3.0% in a long-term toxicity/carcinogenicity study. Each group consisted of 60 males and 60 females. Two concurrent control groups each of 60 males and 60 females received the basal diet. Maximum exposure was 24 months. The no-adverse-effect levels established in this study were 3.0% (an average intake of 4759 mg/kg/day) for male mice and 1.0% (1834 mg/kg/day) for female mice.     

Teratogenic potential of carbaryl given to rabbits and mice by gavage or by dietary inclusion.

The teratogenic potential of the insecticide carbaryl (1-naphthyl methylcarbamate) was evaluated in New Zealand rabbits and CF-1 mice. Rabbits were given 150 or 200 mg carbaryl/kg/day by gavage from Days 6 through 18 of gestation. Mice were given 100 or 150 mg carbaryl/kg/day by gavage or were given a diet containing 5660 ppm of carbaryl (1166 mg carbaryl/kg body wt/day) from Days 6 through 15 of gestation. An increased incidence of omphalocele was observed among the offspring of rabbits given 200 mg carbaryl/kg/day, which was a maternally toxic dose, and another case was observed among the offspring of rabbits given 150 mg/kg/day, a dosage which produced mild maternal toxicity. In comparison, carbaryl was not teratogenic in mice given maternally toxic doses of the compound either by gavage or by dietary inclusion.     

Multigeneration study of FD & C Red No. 3 (erythrosine) in Sprague-Dawley rats

Sprague-Dawley rats received dietary admixtures containing 0.0, 0.25, 1.0 or 4.0% FD & C Red No. 3 (25 rats/sex/group) in a three-generation reproduction study. Each generation was bred twice and breeders for subsequent generations were selected after weaning of the second mating from each generation. There were no compound-related adverse effects on reproductive indices and no gross anomalies were observed. The body weights of parents and pups were significantly reduced (P < 0.05) in all generations at the 4.0% dietary concentration. Maternal body-weight gain during gestation was frequently reduced in the 1.0 and 4.0% groups. The conservative no-observed-adverse-effect level established in this study was 0.25% (approximately 149 and 255 mg/kg body weight/day for males and females, respectively).     

Chronic toxicity/carcinogenicity studies of FD & C Yellow No. 5 (tartrazine) in rats

FD & C Yellow No. 5 was fed to Charles River CD rats as a dietary admixture in two long-term toxicity/carcinogenicity studies. The studies were conducted with an in utero phase in which the compound was administered to the F0 generation rats (60/sex/group) at levels of 0.0, 0.0, 0.1, 1.0 or 2.0% ('original study') and 0.0 or 5.0% ('high-dose study'). The concurrent control groups received the basal diet. After random selection of the F1 animals, the long-term phase was initiated using the same dietary levels with 70 rats of each sex/group, including the three control groups. The maximum exposure to the colouring was 113 and 114 wk for males and females, respectively, in the 'original' study and 122 and 125 wk for males and females, respectively, in the 'high-dose' study. No compound-related effects were noted. The no-adverse-effect level found in this study was 5.0% in the diet providing an average intake of 2641 and 3348 mg/kg/day for male and female rats, respectively.     

The effects of erythrosin B(FD & C Red No. 3) on the guinea-pig ileum myenteric plexus-longitudinal muscle preparation

The responses of the guinea-pig ileum myenteric plexus-longitudinal muscle to the food, drug and cosmetic dye erythrosin B (FD & C Red No. 3) were examined in acetylcholine- and electrically-stimulated preparations. Erythrosin B (10(-6)-10(-4)) reduced the amplitude of the mechanical responses produced by both stimuli. The effects were not simply concentration- and time-dependent. Responses to field stimulation were more sensitive to inhibition by erythrosin B, inhibition increasing with both concentration of dye and time of exposure. Responses to acetylcholine were generally less sensitive to erythrosin B and inhibition at 90 min exposure was more evident at lower concentrations of the dye. Many preparations contracted briefly upon exposure to low concentrations of the dye. Erythrosin B did not significantly affect the specific binding of [3H]QNB to muscarinic receptors. Erythrosin B reduced resting K+ levels in the longitudinal muscle but Na+ concentrations were essentially unaffected. Muscarinic agonist-stimulated uptake of Na+ and release of K+ were inhibited by erythrosin B (10(-6)-10(-4)M); this effect was enhanced with increased time of exposure to the dye. The effects of erythrosin B on cellular ion concentrations were more evident at low than at high concentrations of the dye. Erythrosin B reduced the efflux of [3H]acetylcholine induced by field stimulation from the myenteric plexus longitudinal muscle preparation.     

Chronic toxicity/carcinogenicity study of FD & C Blue No. 2 in mice

Charles River CD-1 mice were fed FD & C Blue No. 2 in the diet levels of 0.5, 1.5 and 5.0% in a long-term toxicity/carcinogenicity study. Each group consisted of 60 males and 60 females. Two concurrent control groups each of 60 males and 60 females received the basal diet. Maximum exposure was 23 months. No consistent compound-related or statistically significant biologically adverse effects were noted.     

Evaluation of the cumulative (repeated application) eye irritation and corneal staining potential of FD & C Yellow No. 5, FD & C Blue No. 1 and FD & C Blue No. 1 Aluminium Lake

A protocol to evaluate the ocular irritation, staining, and embedding potential of FD & C colours (Yellow No. 5, Blue No. 1, Blue No. 1 Aluminium Lake) produced by repeated topical application to rabbit eyes is described. Test materials (3%, w/v in aqueous vehicle) were administered once daily, for a total of 21 days, to the conjunctival sac of the right eye of New Zealand White Rabbits (6 of each sex per group) at a dose volume of 30 μl. Control animals (6 of each sex) received 30 μl of the vehicle daily. All animals survived and were free of significant clinical signs of toxicity throughout the study. Ophthalmoscopic examinations revealed that all animals were free of abnormalities considered to be of clinical importance; all animals were free of significant signs of ocular irritation, staining and particle embedment. The results of this study support the safe use of these materials in consumer products intended for use in the eye area.     

Lifetime toxicity/carcinogenicity studies of FD & C Blue No. 1 (brilliant blue FCF) in rats and mice

FD & C Blue No. 1 was fed to Charles River CD rats and CD-1 mice as a dietary admixture in lifetime toxicity/carcinogenicity studies. The rat study was conducted with an in utero phase in which the compound was administered to the F0 generation rats (60/sex/group) at dietary concentrations of 0.0%, 0.0%, 0.1%, 1.0% or 2.0%. After randomly selecting the F1 animals, the lifetime phase was initiated at the same levels with 70 rats/sex/group, including two control groups. The maximum exposure times were 116 and 111 wk for males and females, respectively. The no-observed-adverse-effect levels are dietary concentrations of 2.0% for males (1072 mg/kg body weight/day), and 1.0% for females (631 mg/kg/day) based on a 15.0% decrease in terminal body weight and decreased survival in the high-dose females compared with the combined control groups. Charles River CD-1 mice (60/sex/group) were fed FD & C Blue No. 1 as a dietary admixture at levels of 0.0%, 0.0%, 0.5%, 1.5% or 5.0% in a lifetime toxicity/carcinogenicity study. The maximum exposure time was 104 wk for both males and females. No consistent, significant compound-related adverse effects were noted. The no-observed-adverse-effect level established in this study is a dietary concentration of 5.0% (7354 mg/kg/day and 8966 mg/kg/day for male and female mice, respectively.     

Chronic toxicity/carcinogenicity study of FD & C Blue No. 2 in rats

FD & C Blue No. 2 was fed to rats in the diet in a long-term toxicity/carcinogenicity study, The study included an in utero phase in which the compound was administered to groups of 60 male and 60 female Charles River CD albino rats at levels of 0.5, 1.0 and 2.0%. Two concurrent control groups, each containing 60 rats of each sex, received the basal diet. After random selection of the F₁ animals, the long-term phase was initiated at the same dietary levels, with 70 rats of each sex in each dose group and in each of two control groups. Maximum exposure was 30 months. No consistent compound-related biologically adverse effects were noted. There were random statistically significant differences from the controls with respect to body weight, food consumption and clinical chemistry tests. Food consumption by the test groups showed a dose-related increase. This was probably due to the non-nutritive character of the colouring. A statistically significant increase in gliomas in the high-dose male rats was not found to be biologically significant, since none of the criteria for determining the neurocarcinogenic potential of chemical substances was met. The overall brain-tumour incidence in this study was within the range typical for 2-yr-old CD rats. Under the conditions of this study, FD & C Blue No. 2 did not produce evidence of any toxicity, including carcinogenicity.     

Developmental toxicity study with triethylene glycol given by gavage to CD rats and CD-1 mice

Triethylene glycol (TEG) is a liquid industrial chemical with a potential for human exposure. The likelihood for developmental toxicity was investigated in two species. Timed-pregnant CD rats and CD-1 mice were dosed daily by gavage with undiluted TEG over gestational days (gd) 5-15 at 0.0 (water control), 1126, 5630 or 11,260 mg kg(-1) day(-1) with rats and 0.0, 563, 5630 or 11,260 mg kg(-1) day(-1) with mice. They were examined daily, and gestational body weights and food and water consumption measured throughout gestation. At necropsy on gd 21 (rats) or gd 18 (mice) dams were examined for body, gravid uterine, liver and kidney weights, and implantation sites. Maternal kidneys were examined histologically. Fetuses were weighed, sex determined, and examined for external, soft tissue and skeletal variations and malformations. Rat dams had reduced body weights, body weight gains, and food consumption, and increased water consumption and relative kidney weights at 11,260 mg kg(-1) day(-1). They also had reduced body weight and increased water consumption at 5630 mg kg(-1) day(-1). Mice had clinical signs and increased relative kidney weight at 11,260 mg kg(-1) day(-1). Renal histology was normal in both species. Neither species had treatment-related effects on corpora lutea or implantations. Fetal body weights were reduced at 11,260 mg kg(-1) day(-1) (both species) and 5630 mg kg(-1) day(-1) (mice). In rat fetuses there was a pattern of delayed ossification in the thoracic region at 11,260 mg kg(-1) day(-1). Mouse fetuses had delayed ossification in the frontal and supraoccipital bones, cervical region, hindlimb proximal phalanges and reduced caudal segments at 11,260 mg kg(-1) day(-1), and in the skull bones at 5630 mg kg(-1) day(-1). These patterns of delayed ossification are consistent with reduced fetal body weights. No biologically significant embryotoxicity or teratogenicity was observed at any dosage in either species. The NOEL for TEG given by gavage over the period of organogenesis was 1126 mg kg(-1) day(-1) in the rat and 5630 mg kg(-1) day(-1) in the mouse for maternal toxicity, and 5630 mg kg(-1) day(-1) (rat) and 563 mg kg(-1) day(-1) (mouse) for developmental toxicology.