7-acetamido-4-hydroxy-3-[[4-[[2-(sulphooxy)ethyl]sulphonyl]phenyl]azo]naphthalene-2-sulphonic acid, sodium salt

Endpoint summary

Key value for chemical safety assessment

Toxic effect type:

dose-dependent

Effects on fertility

Description of key information

No adverse effects on reproduction are expected based on the one generation study of a structural analogue.

Link to relevant study records

Reference

Endpoint:

one-generation reproductive toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

23 Jul 2001 to 12 Dec 2001

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 415 [One-Generation Reproduction Toxicity Study (before 9 October 2017)]

Deviations:

yes

Remarks:

dams were treated and pups reared until day 21 pp. Clinica chemistry was added due to dental defects

Qualifier:

according to guideline

Guideline:

EU Method B.34 (One-Generation Reproduction Toxicity Test)

GLP compliance:

yes

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Details on species / strain selection:

The rat is one of the recommended species according to the OECD TG

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan Winkelmann GmbH, Gartenstrasse 27, 33178 Borchen, Germany
- Age at study initiation: approximately 6 weeks
- Housing: single
- Diet (ad libitum): sniff R/M-Z (V1324)
- Water (ad libitum): tap
- Acclimation period: at least five days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 to 25
- Humidity (%): 30 to 70
- Air changes (per hr): 16-20 air changes per hour
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 31 July 2001 To: 12 December 2001

Route of administration:

oral: gavage

Vehicle:

water

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
The test item was dissolved daily in deionized water in concentrations of 12.5 mg/mL, 50 mg/mL and 200 mg/mL.

VEHICLE: deionized water
- Concentration in vehicle: 12.5 mg/mL, 50 mg/mL and 200 mg/mL
- Amount of vehicle: 5 mL/kg body weight

Details on mating procedure:

- M/F ratio per cage: 1:1 (1:2-mating was performed in three high dose females because of mortality in males due to broken incisors)
- Length of cohabitation: three weeks
- Proof of pregnancy: vaginal plug or sperm in vaginal smear referred to as day 0 of pregnancy
- After successful mating each pregnant female was individually caged

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Stability and homogeneity in the vehicle was measured and verified prior to study start by HPLC.

Duration of treatment / exposure:

Males : 10 weeks pre-mating, treatment continued during mating (ca. 3 weeks)
Females : 4 weeks pre-mating, treatment continued during mating (ca. 3 weeks) and during lactation until day 21 post partum

Frequency of treatment:

daily

Details on study schedule:

NA

Dose / conc.:

1 000 mg/kg bw/day (nominal)

Dose / conc.:

250 mg/kg bw/day (nominal)

Dose / conc.:

62.5 mg/kg bw/day (nominal)

No. of animals per sex per dose:

28

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: The dose rationale was based on a subacute 28-day ora toxicity study with the test compound in rats, which did not show any adverse findings up to and including the limit dose of 1000 mg/kg body weight. Accordingly, dose levels of 0, 62.5, 250 and 1000 mg/kg body weight per day were selected for the present study.

Positive control:

NA

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: The behavior and general health condition of the animals were observed once daily

BODY WEIGHT: Yes
- Time schedule for examinations: once weekly in both sexes during the pre-mating period
in females on day 0, 7, 14 and 21 during gestation and on day 0, 4, 7, 14 and 21 of lactation period.

FOOD CONSUMPTION: Food consumption was recorded together with the body weights (except the mating period for both genders, and except on day 4 of lactation for the females).

Clinical Chemistry
At scheduled sacrifice, 10 male and 10 female animals per group of the P-generation were exanguinated by section of the vena cava cranialis in deep narcosis (CO2 inhalation), and blood was taken for clinical chemistry investigations prior to death.

Clinical chemistry parameters evaluated consisted of the following:
-Glutamyltranspeptidase
Alanine Aminotransferase
(ALAT or GPT)
Albumin
Albumin / Globulin ratio
(calculated)
Alkaline Phosphatase
Aspartate Aminotransferase (ASAT or GOT)
Bilirubin direct
Bilirubin total
Calcium
Chloride (Cl-)
Cholesterol
Creatinine
Globulin (calculated)
Glucose
Inorganic Phosphorous
Potassium (K+)
Sodium (Na+)
Total Protein
Triglycerides
Urea
Uric Acid


Dental examinations
In order to investigate the cause of the dental findings in the late treatment period of the high dose animals, in total five affected incisors of the high dose males and five incisors of the control animals were sent analysed for fluoride, calcium and phosphorous content.

Oestrous cyclicity (parental animals):

daily during mating period

Sperm parameters (parental animals):

Parameters examined in all P male parental generations: testis weight, epididymis weight, prostate weight, seminal vesicles weight
histopathology of testis, epididymis, prostate, seminal vesicles

Litter observations:

STANDARDISATION OF LITTERS
- Performed on day 4 postpartum: yes
- If yes, maximum of 8 pups/litter (4/sex/litter as nearly as possible); excess pups were killed and discarded.

PARAMETERS EXAMINED
The following parameters were examined in F1 offspring: number and sex of pups, stillbirths, live births, postnatal mortality, presence of gross anomalies, weight gain, viability, physical or behavioural abnormalities

GROSS EXAMINATION OF DEAD PUPS:
yes, for external and internal abnormalities; possible cause of death was determined for pups born or found dead.

Postmortem examinations (parental animals):

SACRIFICE
- Male animals: All surviving animals were killed in the third week of the mating period
- Maternal animals: All surviving animals were killed on day 22 (or until day 24, after weekends), after birth. Animals with necropsy date on weekend were killed the next weekday

GROSS NECROPSY
- Gross necropsy consisted of external and internal examinations. All abnormal findings with special attention paid to the organs of the reproductive system were recorded

HISTOPATHOLOGY / ORGAN WEIGHTS
The following tissues or organs (or pieces of them) were preserved in Bouin's solution (testes) and formaldehyde solution and processed for histopathological investigations: Epididymides, Kidneys, Liver, Ovaries with oviducts, Pituitary, Prostate, Seminal vesicle, Testes, Uterus, Vagina, all other gross lesions.
Histopathological examinations were carried out of the control and high dose animals on these organs, as well as on on heart, spleen, lung, pancreas and gastro-intestinal tract from those animals with macroscopically visible changes, i.e., blueish colored pigmentation storage of the test compound.
The following organs were weighed: Epidymides, Kidneys, Liver, Ovaries, Pituitary, Prostate, Seminal vesicle, Testes, Uterus

OTHER: In order to investigate the cause of the dental findings in the late treatment period of the high dose animals, in total five affected incisors of the high dose males and five incisors of the control animals were analyzed for calcium and phosphorous content (two high dose and two control animals, data not presented, filed in the raw data). Secondly they were extended to fluoride, calcium and phosphorous content on the remaining 3 high dose incisors and control incisors.

Postmortem examinations (offspring):

SACRIFICE
- The F1 offspring not selected as parental animals were sacrificed at 4 days of age.
- Dead or moribund pups and pups killed at day 4 were examinated for defects.

- All surviving F1-animals were killed on day 22 (or until day 24, after weekends), after birth. Animals with necropsy date on weekend were killed the next weekday

Statistics:

All Parameters: The assumption of a monotonic dose-response relationship for all parameters justifies the restriction of the significance level to 5 percent (per parameter and sex), using the method of: HOTHORN L, LEHMACHER W.: A Simple Testing Procedure "Control versus k Treatments" for One-sided Ordered Alternatives, with Application in Toxicology, Biom. J. 33, 179-189, Akademie Verlag
Bodyweights: The changes of parameter values compared to the treatment-free baseline values are analyzed with the t-Test:
HARTUNG J., ELPERT B., KLÖSENER K. H., Lehr- und Handbuch der angewandten
Statistik (1989), R. Oldenbourg Verlag, München
Clinical Pathology Data: Wilcoxon's Test: HOLLANDER M., WOLFE, D. A:, Nonparametric statistical methods
Organ weights (absolute): t-Test
Organ weights (relative to bodyweight): Wilcoxon's Test

Reproductive indices:

Copulatory index (%): Number of sperm positive females x 100 / Number of mated females
Fertility index - Males (%): Number of fertile males x 100 / Number of mated males
Fertility index - Females (%): Number of pregnant females x 100 / Number of mated females
Gestation index (%): Number of females with viable pups x 100 / Number of pregnant females
Sex ratio: (Number of pups examined - Number of males (females)) x 100 / Number of pups examined

Offspring viability indices:

Intra uterine mortality: (Number of implantations - Number of newborns) x 100 / Number of implantations
Total mortality: (Number of implantations - Number of viable pups) x 100 / Number of newborns
Viability index (%): Number of viable pups on day 4 (7, 14, 21) x 100 / Number of viable pups on day 0 (4, 7, 14)
Lactation index (%): Number of viable pups on day 21 x 100 / Number of viable pups on day 0 of lactation
Weaning index (%)

Clinical signs:

effects observed, treatment-related

Description (incidence and severity):

In the mid-dose group, 4 males showed broken-off upper and/or lower incisors, resulting into stilted gait and quatting posture in two of the animals.
In the high dose group, the lower and/or upper incisors were white discolored from week 5 onwards, and generally broke off within a few days. In particular some of those animals developped general clinical signs (stilted gait, hypoactivity, coat bristling, irregular respiration, respiratory sounds diarrhea, snout encrusted blood colored or swollen etc.) and some of those ended up in a general poor condition. This was mainly due to the fact that they could not take up food properly. These effects were secondary effects of hyperflourosis.

Mortality:

mortality observed, treatment-related

Description (incidence):

In the high dose group (1000 mg/kg body weight), 1 male and 1 female animal was found dead early (days 19 and 5, respectively) with unknown pathogenesis. In addition, further 6/28 males and 4/27 females were found dead or had to be killed on human grounds from study week 6-7 onwards, due to severely broken off- and white-discolored incisors, generally starting to occur from study week 6 onwards. These effects were secondary effects of hyperflourosis.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Body weight gain was significantly decreased for high dose males (10% within the first 6 weeks), with subsequent marked loss of body weight up to the end of treatment. In the high dose females, body weight gain was slightly increased during the first 4 weeks (pre-mating period), which, however, had turned back to a slight decrease during the gestation period (based on pregnant females only), and subsequent marked loss of body weight during lactation in surviving females. There was marked loss of body weights in high dose animals that had dental problems. These effects were secondary effects of hyperflourosis.

Food efficiency:

effects observed, treatment-related

Description (incidence and severity):

Those high dose animals that were found dead from week 6 onwards or were killed on human grounds did not take up food a few days before death. Mean absolute food consumption in all remaining animals of the high dose group (1000 mg/kg) was slightly to moderately decrerased. This was in line with the lower body weight gains recorded for this group. Hence, relative food consumption was generally comparable in all groups throughout the study, except for high dose females, who exhibited a significant decrease of relative food consumption during the lactation period. These effects were secondary effects of hyperflourosis.

Clinical biochemistry findings:

no effects observed

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Relevant histopathological findings in parental animals of the high-dose group 4 at terminal killing were as follows:
Stomach: Mixed cellular infiltrations in the submucosal area in particular for the males. The appearance of inflammatory cells in the submucosal area of the stomach is obviously a sign of irritation caused by the high salt content of the test compound.
Kidneys: appearance of intratubular pigment in 10 male and 5 female animals. Single animals exhibited degenerations or necrosis of tubular cells. The intracellular storage of pigment in the kidneys is probably caused by the test compound, which was not released by the tubular cells after filtration.
Liver: Increased number of necrotic/apoptotic cells; one animal stained with oil red as a random sample showed a peripheral fatty change. The alterations in the liver did not reveal a general toxicological effect but emphasize a state of starvation as a result of disability of food uptake. This effect is a secondary effect of hyperflourosis.

Other effects:

effects observed, treatment-related

Description (incidence and severity):

Bluish discoloured faeces and/or urine were observed in the mid- and high-dose groups.

Dental examinations reveals a 3-fold higher amout of fluor in the incisors of high-dose animals compared to controls.

Reproductive function: oestrous cycle:

no effects observed

Reproductive function: sperm measures:

not examined

Reproductive performance:

effects observed, treatment-related

Description (incidence and severity):

In the high dose group, only 23/27 females were detected sperm positive and recorded as being successfully mated. Mating for female Nos. 207, 210, 213 was still unsuccessful after 21 days. These three females were killed on day 49 of the study. The mean pre coital interval of the remaining high-dose group females was slightly prolonged, i.e., to 7.9 days, (10.7 days, when taking both intervals together for 2 different males, each mating with female Nos. 199, 201, 204). These effects were secondary effects of hyperflourosis.

CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS)
There were no intercurrent deaths in the control-, low- and mid-dose group animals. In the high dose group (1000 mg/kg body weight), 1 male and 1 female animal was found dead early with unknown pathogenesis. In addition, further 6/28 males and 4/27 females were found dead or had to be killed on human grounds from study week 6-7 onwards. Animal No. 128 was killed by mistake on day 51.

Behavior and health status was not affected in low- and mid-dose group animals with the exception of 4 males exhibiting broken off incisors from week 6 onwards. Several high-dose animals had broken off- and white-discolored incisors, generally starting to occur from study week 6 onwards. Some of those animals developped general clinical signs (stilted gait, hypoactivity, coat bristling, irregular respiration, respiratory sounds diarrhea, snout encrusted blood colored or swollen etc.) and some of those ended up in a general poor condition.

Blue discolored feces were observed in all P-generation male and female animals of the 250 and 1000 mg/kg body weight groups.

BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS)
Body weight gain was significantly decreased for high dose animals that had dental problems.
Those high dose animals that were found dead from week 6 onwards or were killed on human grounds did not take up food a few days before death. Mean absolute food consumption in all remaining animals of the high dose group (1000 mg/kg) was slightly to moderately decrerased. This was in line with the lower body weight gains recorded for this group. Hence, relative food consumption was generally comparable in all groups throughout the study, except for high dose females, who exhibited a significant decrease of relative food consumption during the lactation period

REPRODUCTIVE FUNCTION: ESTROUS CYCLE (PARENTAL ANIMALS)
There were no test item related differences in the estrous cycle.

REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS)
Due to the lower food consumption resulting from broken-off incisors the pregnancy index was lower in high-dose females
The mean number of implantations counted, mean live pups/litter, birth index were comparable in all groups. In addition, supernumerary
implantation sites, percentage of implantations, were not influenced by administration of the test compound.
Mean gestation length was comparable in all groups.

ORGAN WEIGHTS
In high dose males, liver, kidney, testes, epididymides, prostate and seminal vesicles weight were slightly lower, with statistical significance, which was due to the reduction of terminal body weight and hence, not related to target organ toxicity.
The same applied for high dose females, where liver, kidney and uterus weight was slightly lower, with statistical significance.

GROSS PATHOLOGY (PARENTAL ANIMALS)
Males and females from the mid-dose group exhibited kidneys with dark brown discolorations. In addition, the kidneys of one male in this groups was bluish discolored.
The main relevant findings were discolorations in several organs animals of the high dose group. Further major alterations were white discolored or broken incisors in nearly all animals of this group.

HISTOPATHOLOGY (PARENTAL ANIMALS)
Histopathological findings in parental animals of the high-dose group at terminal killing revealed intratubular pigment in kidneys in 10 male and 5 female animals. Single animals exhibited degenerations or necrosis of tubular cells. Increased number of necrotic/apoptotic cells were found in the liver. Mixed cellular infiltrations in the submucosal area of the stomach were found particular in males.

Dose descriptor:

NOAEL

Remarks:

General health

Effect level:

250 mg/kg bw/day (nominal)

Sex:

male/female

Basis for effect level:

clinical signs

mortality

body weight and weight gain

food efficiency

organ weights and organ / body weight ratios

gross pathology

histopathology: non-neoplastic

other: All effects observed were secondary effects due to broken-off incisors resulting in lower food consumption and a lower pregnancy index. This effect was due to fluorosis of the rats' teeth caused by the 0.3% fluor impurity

Dose descriptor:

NOAEL

Remarks:

Reproductive performance

Effect level:

1 000 mg/kg bw/day (nominal)

Sex:

male/female

Basis for effect level:

reproductive performance

Critical effects observed:

no

Clinical signs:

no effects observed

Mortality / viability:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Observation of live pups during lactation in the high-dose group (1000 mg/kg bw.) indicated that, in particular for those dams, being in a state of starvation, did not suckle their offspring sufficiently, which was visible by low amount of milk in the pups body.
Accordingly, the mean body weight of live pups during lactation was significantly decreased in the high dose offspring (1000 mg/kg bw.) from day 14, post partum onwards. These effects were secondary effects of hyperflourosis.
Mean body weight was not affected in any other group.

Sexual maturation:

not specified

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

no effects observed

Histopathological findings:

not examined

VIABILITY (OFFSPRING)
no effects

CLINICAL SIGNS (OFFSPRING)
no effects

BODY WEIGHT (OFFSPRING)
Mean body weight of live pups during lactation was significantly decreased in the high dose offspring (1000 mg/kg bw.) from day 14, post partum onwards. Mean body weight was not affected in any other group

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

1 000 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

body weight and weight gain

Critical effects observed:

no

Reproductive effects observed:

no

Conclusions:

Daily oral administration of the test substance to rats during the premating, mating, gestation and lactation period at dose levels of 62.5 or 250 mg/kg body weight did not affect food consumption, body weight development, male or female mating/reproductive performance, fertility, gestation length as well as development of their progenity.
Daily oral administrations of 1000 mg/kg body weight (high-dose group) were well tolerated in rats within the first 5 weeks of treatment, but thereafter, from week 6 onwards, caused mortality due to dental lesions with subsequent disability of food uptake and starvation (clinical picture of dental fluorosis). This finding was time-dependent, with a threshold dose of 250 mg/kg body weight for males, and could be related to the fluoride impurity (0.3%) of this batch tested.
Although there was marked pigment storage of the test compound in several organs, there was no clear functional or histopathological correlate that could be related to compound-induced systemic toxicity and/or specific reproductive toxicity. Impairment of reproduction and fertility at high dose parental animals was primarily the result of severe dental problems.
In the presence of severe dental problems at 1000 mg/kg bw and threshold dose of 250 mg/kg bw for this finding, there was no evidence of selective reproductive toxicity in rats.

Executive summary:

The present study was conducted in order to determine the effects of the test substance on reproduction when administered orally by gavage to male and female Sprague Dawley rats during pre-mating, mating, gestation and lactation.

Groups of 28 male and 28 (27 in the high-dose group) female Spraque Dawley rats received the test substance orally once daily at dose levels of 0, 62.5, 250 or 1000 mg/kg body weight for a period of 10 weeks (males) and 4 weeks (females), prior to mating. Dosing of males was continued during the whole mating period until sacrifice (approx. week 11 - 13 of the study). Treatment of mated females was continued until day 21 after littering. The dosing volume was 5 mL/kg, corresponding to concentrations of 0, 12.5, 50 and 200 mg/mL. At start of the study, the animals were 5-9 weeks of age with mean body weights of 240 g for males, and 206 g for females.

Behavior and state of health were observed daily in all groups. Body weight development and food consumption were recorded throughout the study in females, and during pre-mating period in males. After the mating period the males were killed and necropsied. The dams were allowed to litter and rear their progeny to the stage of weaning. Growth, development and behavior of the progeny were assessed during lactation. The dams as well as surviving pups were killed on day 22-24 post partum. Animals scheduled for necropsy on weekend were killed the next weekday.

At the time of sacrifice or death during the study the animals of the P generation were examined for macroscopically visible abnormalities. The main organs were weighed and the organ to body weight ratios calculated. Special attention was paid to the organs of the reproductive system. Histopathology of listed organs was performed in case of macroscopic visible changes. Moreover, dental mineral analyses (fluoride, calcium and phosphorus) were performed externally. In addition, clinical chemistry investigations, in particular for serum electrolytes, were performed in 10 animals per sex and group as amended to the protocol.

Body weights, food consumption, clinical chemistry data, absolute and relative organ weights and litter parameters were analyzed with the aid of a statistical program to show differences compared to the controls.

RESULTS

High-dose group (1000 mg/kg body weight): There were 7 males and five females that were found dead or killed on humane grounds due to starvation and bad general health condition as a cause of broken off incisors and subsequent disability of food uptake. In addition, one female was killed with dead pups at birth, another one with live pups was killed on lactation day 6 due to

inability to suckle them properly. Teeth trimming were carried out to insure food uptake during mating procedures for as many animals concerned as possible. Mean food consumption and body weight development was decreased during pre-mating (males) and during the lactation period (surviving females). Mean gestation length, (ca. 23.0 days), was not affected. Because of these

unscheduled deaths the number of pregnancies was markedly reduced (12 cf./22 of control). The absolute number of females at term with live pups was reduced (11 cf./21 of control), with lower absolute number of implantations. One dam had dead pups only. However, relative numbers of live pups, the mean number of implatations and birth index, was not adversely affected when

related to the number of females at term with live pups. During early lactation, 4/11 females had to be killed on humane grounds, as they were not able to rear their healthy offspring due to starvation. The remaining 7 females reared their healthy offpring up to the end of the lactation period, however, mean pup body weight gains were significantly decreased from day 14 post partum up to the end of the study. Mean viability index, weaning index, survival rate at day 21 was not affected. There was 1 unreared litter recorded for this group. The pups did not show any macroscopically visible abnormalities.

Apart from significantly decreased total bilirubin levels, clinical pathology was unobstrusive, also with regard to serum electrolytes. Anatomic pathology revealed severe dental lesions (broken off, deformed and white discolored incisors), which were confirmed to contain a 3-fold concentration of fluoride. Fluoride (0.3%) was identified as an impurity of the test compound batch, tested in

this study. Massive bluish discolorations of the whole carcasse and in several inner organs were also detected at necropsy. Microscopy confirmed intratubular pigment storage in the kidneys, increased number of necrotic/apoptotic cells in the liver as a histopathological correlate of clinical starvation, and mixed cellular infiltrations in the submucosal area of the stomach, probably as a

result of irritating effects of the high salt content of the test compound. There were no selective changes in sexual organs that could be related to selective reproductive toxicity in these dose group animals, nor were there any correlates of target organ toxicity.

Mid-dose group (250 mg/kg body weight): There were no premature deaths. No compound related clinical findings were recorded for the females. Four males had broken-off incisors during the late treatment period (weeks 6 -12). However, food consumption, body weight development, mating and reproductive performance, fertility, mean gestation length, rearing and development of their

offspring remained unaffected by administration of the test compound. Clinical chemistry, as well as anatomic pathology (necropsy, organ weights, histopathology) in particular of the sexual organs were generally unobstrusive, apart from pigment storage (dark brownish/or bluish discolorations) in the kidneys.

Low-dose group (62.5 mg/kg body weight): There were no premature deaths. No compound-related clinical signs were recorded in the P-generation male and female animals. Food consumption, body weight development, mating and reproductive performance, fertility, mean gestation length, rearing and development of their offspring remained unaffected by administration of the test compound. Clinical Chemistry, as well as anatomic pathology (necropsy, organ weights, histopathology) in particular of the sexual organs were unobstrusive.

Effect on fertility: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Study duration:

subchronic

Species:

rat

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

The present study was conducted in order to determine the effects of the test substance on reproduction when administered orally by gavage to male and female Sprague Dawley rats during pre-mating, mating, gestation and lactation.

Groups of 28 male and 28 (27 in the high-dose group) female Sprague Dawley rats received the test substance orally once daily at dose levels of 0, 62.5, 250 or 1000 mg/kg body weight for a period of 10 weeks (males) and 4 weeks (females), prior to mating. Dosing of males was continued during the whole mating period until sacrifice (approx. week 11 - 13 of the study). Treatment of mated females was continued until day 21 after littering. The dosing volume was 5 mL/kg, corresponding to concentrations of 0, 12.5, 50 and 200 mg/mL. At start of the study, the animals were 5-9 weeks of age with mean body weights of 240 g for males, and 206 g for females.

Behavior and state of health were observed daily in all groups. Body weight development and food consumption were recorded throughout the study in females, and during pre-mating period in males. After the mating period the males were killed and necropsied. The dams were allowed to litter and rear their progeny to the stage of weaning. Growth, development and behavior of the progeny were assessed during lactation. The dams as well as surviving pups were killed on day 22-24 post partum. Animals scheduled for necropsy on weekend were killed the next weekday.

At the time of sacrifice or death during the study the animals of the P generation were examined for macroscopically visible abnormalities. The main organs were weighed and the organ to body weight ratios calculated. Special attention was paid to the organs of the reproductive system. Histopathology of listed organs was performed in case of macroscopic visible changes. Moreover, dental mineral analyses (fluoride, calcium and phosphorus) were performed externally. In addition, clinical chemistry investigations, in particular for serum electrolytes, were performed in 10 animals per sex and group as amended to the protocol.

Body weights, food consumption, clinical chemistry data, absolute and relative organ weights and litter parameters were analyzed with the aid of a statistical program to show differences compared to the controls.

High-dose group (1000 mg/kg body weight): There were 7 males and five females that were found dead or killed on humane grounds due to starvation and bad general health condition as a cause of broken off incisors and subsequent disability of food uptake. In addition, one female was killed with dead pups at birth, another one with live pups was killed on lactation day 6 due to

inability to suckle them properly. Teeth trimming were carried out to insure food uptake during mating procedures for as many animals concerned as possible. Mean food consumption and body weight development was decreased during pre-mating (males) and during the lactation period (surviving females). Mean gestation length, (ca. 23.0 days), was not affected. Because of these

unscheduled deaths the number of pregnancies was markedly reduced (12 cf./22 of control). The absolute number of females at term with live pups was reduced (11 cf./21 of control), with lower absolute number of implantations. One dam had dead pups only. However, relative numbers of live pups, the mean number of implatations and birth index, was not adversely affected when related to the number of females at term with live pups. During early lactation, 4/11 females had to be killed on humane grounds, as they were not able to rear their healthy offspring due to starvation. The remaining 7 females reared their healthy offpring up to the end of the lactation period, however, mean pup body weight gains were significantly decreased from day 14 post partum up to the end of the study. Mean viability index, weaning index, survival rate at day 21 was not affected. There was 1 unreared litter recorded for this group. The pups did not show any macroscopically visible abnormalities.

Apart from significantly decreased total bilirubin levels, clinical pathology was unobstrusive, also with regard to serum electrolytes. Anatomic pathology revealed severe dental lesions (broken off, deformed and white discolored incisors), which were confirmed to contain a 3-fold concentration of fluoride. Fluoride (0.3%) was identified as an impurity of the test compound batch, tested in this study. Massive bluish discolorations of the whole carcasse and in several inner organs were also detected at necropsy. Microscopy confirmed intratubular pigment storage in the kidneys, increased number of necrotic/apoptotic cells in the liver as a histopathological correlate of clinical starvation, and mixed cellular infiltrations in the submucosal area of the stomach, probably as a result of irritating effects of the high salt content of the test compound. There were no selective changes in sexual organs that could be related to selective reproductive toxicity in these dose group animals, nor were there any correlates of target organ toxicity.

Mid-dose group (250 mg/kg body weight): There were no premature deaths. No compound related clinical findings were recorded for the females. Four males had broken-off incisors during the late treatment period (weeks 6 -12). However, food consumption, body weight development, mating and reproductive performance, fertility, mean gestation length, rearing and development of their offspring remained unaffected by administration of the test compound. Clinical chemistry, as well as anatomic pathology (necropsy, organ weights, histopathology) in particular of the sexual organs were generally unobstrusive, apart from pigment storage (dark brownish/or bluish discolorations) in the kidneys.

Low-dose group (62.5 mg/kg body weight): There were no premature deaths. No compound-related clinical signs were recorded in the P-generation male and female animals. Food consumption, body weight development, mating and reproductive performance, fertility, mean gestation length, rearing and development of their offspring remained unaffected by administration of the test compound. Clinical Chemistry, as well as anatomic pathology (necropsy, organ weights, histopathology) in particular of the sexual organs were unobstrusive.

In contrary to Reactive Orange 72/78, the structural analogue contains a mono-chloro, di-fluoro-pyrimidine group. This led to a higher content (0.3%) of fluoride in the test substance resulting in fragility of the incisors and a very low food uptake in high-dose dams. Consequently, the survival rate in the high-dose group was rather low. Daily oral administrations of 1000 mg/kg body weight were well tolerated in rats within the first 5 weeks of treatment, but thereafter, from week 6 onwards, caused mortality due to dental lesions with subsequent disability of food uptake and starvation (clinical picture of dental fluorosis). Consequently, due to the fact that no fluoride is contained in Reactive Orange 72/78, a NOAEL of 1000 mg/kg body weight is expected for the test substance for parental reproductive performance and their offspring.

Effects on developmental toxicity

Description of key information

No adverse effects on development of offspring are expected based on the developmental toxicity study of a structural analogue.

Link to relevant study records

Reference

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Study period:

14 September to 25 November 1993

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

GLP compliance:

yes

Limit test:

yes

Species:

rat

Strain:

Wistar

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Hoechst AG
- Age at study initiation: 65 to 75 days
- Weight at study initiation: 193.1 +/- 14.2
- Fasting period before study: NA
- Housing: single
- Diet: Altromin 1310 ad libitum
- Water: tap water ad libitum
- Acclimation period: 7 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 to 22°C
- Humidity (%): 48 to 61%
- Air changes (per hr): 16 to 20
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 14. Sep To: 25. Nov 1993

Route of administration:

oral: gavage

Vehicle:

water

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
- Frequency of preparation: daily
- Administration: within 3 hours after preparation

VEHICLE
- Concentration in vehicle: 200 mg/kg nominal
- Amount of vehicle (if gavage): 5 ml/kg

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

-

Details on mating procedure:

- Impregnation procedure: cohoused
- M/F ratio per cage: 1:1
- Length of cohabitation: over night (3:30 pm to 7:30 am next day)
- Verification of same strain and source of both sexes: yes - own breeding facility
- Proof of pregnancy: sperm in vaginal smear, referred to as day 1 of pregnancy

Duration of treatment / exposure:

7. - 16. day of pregnancy

Frequency of treatment:

daily

Duration of test:

cesarean section on Day 21 of pregnancy

No. of animals per sex per dose:

20 to 24 mated females

Control animals:

yes

Details on study design:

- Dose selection rationale: test item was tolerated in the acute and subacute studies without adverse effects

Maternal examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: daily

BODY WEIGHT: Yes
- Time schedule for examinations: weekly

FOOD CONSUMPTION AND COMPOUND INTAKE : Yes
- Time schedule for examinations: weekly
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/100 g body weight/day: Yes

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 21
- Organs examined: all organs examined macroscopically
uterus - live and dead fetuses, resorption sites, placentas
ovaries - corpora lutea

OTHER:
- diameter of conceptuses undergoing resorption
- placenta weights
- presence of iron in uterus walls with ammonium sulphide to detect invisible implantation sites

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: No
- Placenta weight: Yes
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes

Fetal examinations:

- External examinations: Yes: all per litter
- Body weight: Yes: all per litter
- Crown-rump length: Yes: all per litter
- Soft tissue examinations: Yes: half per litter
- Skeletal examinations: Yes: half per litter
- Head examinations: No data

Statistics:

comparison to actual control group and historical controls
MANOVA: body weight development, fetal weight, placental weight
PURI&SEN rank order test: food intake
Mantel-Haenszel's chi-squared test: live fetuses, intrauterine fetal death, number of implants, number of corpora lutea
multivariate analysis of variance: litter means of fetal weights, crown-rump length, placental weights
Fisher test: autopsy findings, body cross-sections, skelettal examination

Dams which had no live fetuses were excluded from the calculation of mean values and statistical evaluation

Indices:

No data

Historical control data:

Yes

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Food efficiency:

no effects observed

Gross pathological findings:

no effects observed

Details on results:

Clinical examinations
The dams of the compound group and the control dams showed no impairment to behaviour and General condition and survived until the scheduled study end. All dams in the compound group excreted black-discoloured faeces on at least eight days during and after the treatment period, mostly, however, in the period from day 8 - 19 of pregnancy. Blue-discoloured urine was voided by three dams from days 8 - 10 or days 8 - 11 of pregnancy. One dam from the compound group displayed pallor from day 8 - 11 of pregnancy. Compound solution escaped from the mouths of two dams after the 3rd and/or 4th administration, presumably due to the dosing method. The amounts, however, were small and without relevance for assessing the test compound. Local abdominal hair loss was noted in another dam from the compound group on days 20 and 21 of pregnancy.
The administration of C. I. Reactive Black 5 had no influence on the feed consumption of the dams. The dams consumed comparable amounts of feed to those of the controls both during and after the treatment period.
The body weight gain of the dams treated with C. I. Reactive Black 5 was likewise unaffected. The dams treated with the test compound gained in weight to the same extent as the controls.
Autopsy of the dams
The concluding autopsy revealed a marked dilatation of one renal pelvis in one dam each from the compound and control groups. No further alterations to the internal organs could be seen in the macroscopic examination.

Number of abortions:

no effects observed

Pre- and post-implantation loss:

no effects observed

Total litter losses by resorption:

no effects observed

Early or late resorptions:

no effects observed

Dead fetuses:

no effects observed

Changes in pregnancy duration:

no effects observed

Changes in number of pregnant:

no effects observed

Details on maternal toxic effects:

Examinations after caesarean section
All 20 dams in the compound group and 19 dams in the control group carried live conceptuses to term and were delivered by caesarean section. One control dam had no live foetuses, but merely 8 empty implantation sites in the uterus, indicating early embryonic death shortly after implantation. In this animal, the corpora lutea were quite small and could not therefore be determined exactly. The number of corpora lutea, which provides information on the number of ovulations prior to start of treatment, and the number of implants and live foetuses in the remaining dams of the compound group did not differ markedly from those of the control animals and lay in the range of our previous control values.

Key result

Dose descriptor:

NOAEL

Effect level:

>= 1 000 mg/kg bw/day (nominal)

Remarks on result:

not determinable due to absence of adverse toxic effects

Key result

Abnormalities:

no effects observed

Fetal body weight changes:

no effects observed

Reduction in number of live offspring:

no effects observed

Changes in sex ratio:

no effects observed

Changes in litter size and weights:

no effects observed

External malformations:

no effects observed

Skeletal malformations:

no effects observed

Visceral malformations:

no effects observed

Details on embryotoxic / teratogenic effects:

Examination of foetuses
The live foetuses delivered in the compound group were normally developed. Their body weights and lengths did not differ from those of the control foetuses and lay in the range of our previous control values. The number of live foetuses weighing less than 3.0 g and thus qualifying according to our definition as slightly retarded or retarded was even lower than that of the control group. The sex ratio was relatively balanced in both groups: the males predominated slightly in the control group and the females predominated slightly in the compound group.
Dead embryofoetal primordia were found in both groups. They consisted exclusively of conceptuses undergoing resorption. These had died at a relatively early stage and exhibited diameters of up to 6.3 mm (compound group) or 6.6 mm (control group). Dead foetuses were not found in either of the two groups. The number of dead embryofoetal primordia in the dams of the compound group was low and did not differ from that of the control dams.
The placentas of the foetuses in the compound group were unremarkable macroscopically and in respect of their weights, which corresponded to those of the control group.
The findings observed at the morphological examination of the foetuses show that no malformations appeared in any foetus in the compound group. One control foetus exhibited a right-sided microphthalmia.
The autopsy and body cross-section examinations revealed blood in the pericardium or abdominal cavity, completely fused or bipartite pulmonary lobes or a haematoma in a liver lobe as well as a distention of one or both renal pelves or one ureter in individual or some foetuses. Furthermore, one foetus in the compound group displayed blood in the vicinity of the right kidney. Findings confined to individual foetuses in the control group were: blood in the thoracic cavity or in the right kidney and a stomach which was relatively large and tautly filled with fluid.
The skeletons of the foetuses in the compound group were at roughly the same stage of development as those of the control foetuses. Their stage of ossification corresponded to the 21st day of pregnancy. The number of foetuses in the substance-treated group displaying a poor or missing ossification of sternebrae, 5th metacarpal bone and the ossification of fewer than two caudal vertebral centres did not differ markedly from that of the control foetuses. The number of foetuses in which individual cranial bones were not-yet or only poorly ossified was, significantly increased compared to the simultaneous control group but still lay within the range of previous control values (maximum frequency 61.5 %).
Apart from these findings, individual or several foetuses in both groups exhibited longitudinally displaced, dislocated, fragmented sternebrae or waved and/or thickened ribs while numerous foetuses displayed an additional short rib anlage, uni- or bilaterally, at the 1st lumbar vertebra. In individual foetuses of the compound group, a dysplastic 10th or 11th and 12th thoracic vertebral centre or a 14th thoracic vertebra with a short, analogous rib pair were observed. Three foetuses in the control group showed an additional short rib, left- or both-sided, at the 7th cervical vertebra.

Key result

Dose descriptor:

NOAEL

Effect level:

>= 1 000 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Remarks on result:

not determinable due to absence of adverse toxic effects

Key result

Abnormalities:

no effects observed

Key result

Developmental effects observed:

no

Conclusions:

No adverse effects were observed after daily administration of 1000 mg/kg/day in dams or their fetuses.
Maternal NOEL: 1000 mg/kg bw/day
Fetal NOEL: 1000 mg/kg bw/day

Executive summary:

In this limit test, the test substance, dissolved in distilled water, was administered orally by stomach tube in a single daily dose of 1000 mg/kg body weight to a group of 20 pregnant female Wistar rats from the 7th - 16th day of pregnancy. A simultaneous control group of the same size received the vehicle without test compound. On the 21st day of pregnancy, the dams were killed and delivered by caesarean section. The foetuses delivered by caesarean section were then examined morphologically for developmental disorders.

The study showed that the repeated oral administration of the test substance, at a dose of 1000 mg/kg body weight in the sensitive phase of organogenesis for the conceptuses, did not lead to any impairment of the general physical condition of the dams or impaired intrauterine development of conceptuses.

The morphological examination of the foetuses with regard to stage of development, outwardly detectable anomalies as well as anomalies of the internal organs and the skeleton showed no indication of an embryotoxic or teratogenic effect of the compound. The findings observed are to be regarded as spontaneous in origin.

On the basis of the results of this limit test, the “no observed adverse effect level” in rats following oral administration lies at 1000 mg/kg body weight/day or above with regard to maternal and embryofoetal toxicity and teratogenicity.

No teratogenic effect was observed.

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Study duration:

subacute

Species:

rat

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Additional information

In this limit test, the test substance, dissolved in distilled water, was administered orally by stomach tube in a single daily dose of 1000 mg/kg body weight to a group of 20 pregnant female Wistar rats from the 7th - 16th day of pregnancy. A simultaneous control group of the same size received the vehicle without test compound. On the 21st day of pregnancy, the dams were killed and delivered by caesarean section. The foetuses delivered by caesarean section were then examined morphologically for developmental disorders.

The study showed that the repeated oral administration of the test substance, at a dose of 1000 mg/kg body weight in the sensitive phase of organogenesis for the conceptuses, did not lead to any impairment of the general physical condition of the dams or impaired intrauterine development of conceptuses.

The morphological examination of the foetuses with regard to stage of development, outwardly detectable anomalies as well as anomalies of the internal organs and the skeleton showed no indication of an embryotoxic or teratogenic effect of the compound. The findings observed are to be regarded as spontaneous in origin.

On the basis of the results of this limit test, the “no observed adverse effect level” in rats following oral administration lies at 1000 mg/kg body weight with regard to maternal and embryofoetal toxicity and teratogenicity.

No teratogenic effect was observed.

Justification for classification or non-classification

The above studies have all been ranked reliability 1 according to the Klimisch et al system. This ranking was deemed appropriate because the studies were conducted to GLP an in compliance with agreed protocols. Sufficient dose ranges and numbers are detailed; hence it is appropriate for use based on reliability and animal welfare grounds. As the effects are considered adaptive rather than toxicological, no classification is proposed.

The above results triggered no classification under the CLP Regulation (EC No 1272/2008). No classification for prolonged effects is therefore required.