Acetic acid, 2,2-difluoro-2-[[2,2,4,5-tetrafluoro-5-(trifluoromethoxy)-1,3-dioxolan-4-yl]oxy]-, ammonium salt (1:1)

Developmental toxicity / teratogenicity

Administrative data

Endpoint:

developmental toxicity

Type of information:

experimental study

Remarks:

(The study was performed to comply with a Regulation outside Europe)

Adequacy of study:

key study

Study period:

From 10-APR-2013 to 05-JUN-2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

GLP study conducted according to OECD Guideline 414 without major deviation.

Cross-reference

Reason / purpose for cross-reference:

reference to other study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2014

Report date:

2014

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

no

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

ammonium 2,2-difluoro-2-{[2,2,4,5-tetrafluoro-5-(trifluoromethoxy)-1,3-dioxolan-4-yl]oxy}acetate

EC Number:

682-238-0

Cas Number:

1190931-27-1

Molecular formula:

C6H4F9NO6

IUPAC Name:

ammonium 2,2-difluoro-2-{[2,2,4,5-tetrafluoro-5-(trifluoromethoxy)-1,3-dioxolan-4-yl]oxy}acetate

Test material form:

other: liquid

Details on test material:

- Name of test material (as cited in study report): cC6O4 (Alternative names : C6O4 cyclic, cC6O4 NH4 salt, cC6O4 Ammonium salt aqueous solution, Aqueous solution of cyclic C6O4 ammonium salt)
- Analytical purity: 39.8% (water solution)
- Composition of test material, percentage of components: c-C604NH4 = 39.8% w, Organic impurity C9 = 0.2%, water = 60%
- Lot/batch No.: 320020
- Expiration date of the lot/batch: 31 December 2020
- Storage condition of test material: Room temperature
- Stability under test conditions: The stability was checked prior to commencement of treatment and was found to be 24 hours at room temperature in the concentration range of 0.5 to 8 mg/mL. In the chemical analysis studies, the 24 hour stability at room temperature was verified in the range from 0.03 to 20 mg/mL. The software used for this activity will be the Empower® Pro build No. 2154. Acceptance criterion: Final results for all levels were within the acceptability limits stated in RTC SOPs for concentration (90-110%). Results: Results of all analyses were within the limits of acceptance.

Test animals

Species:

rat

Strain:

Sprague-Dawley

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Italy S.p.A., Calco (Lecco), Italy.
- Age at study initiation: 9 weeks old for females, 11 weeks for males.
- Weight at study initiation: 204-234 g for females, at least 340 g for males.
- Housing: The animals were housed in a limited access rodent facility. During the pre-pairing period and after mating, the animals were housed no more than 5 of one sex to a cage in Polysulfone cages measuring 59.5x38x20 cm. During the mating period, the rats were housed on the basis of 1 male to 1 female in clear polysulfone cages measuring 42.5x26.6x18.5 cm with a stainless steel mesh lid and floor (Techniplast Gazzada S.a.r.l., Buguggiate, Varese).
- Diet: 4 RF 21 (Mucedola S.r.l., Via G. Galilei, 4, 20019, Settimo Milanese (MI), Italy) laboratory rodent diet, ad libitum
- Water: drinking water supplied via water bottles, ad libitum
- Acclimation period: 12 days

ENVIRONMENTAL CONDITIONS
- Temperature: 22 ± 2 °C
- Humidity: 55 ± 15 %
- Air changes: approximately 15 to 20 per hour
- Photoperiod: 12 h dark / 12 h light

IN-LIFE DATES: From: 30-April-2013 To: 29-May-2013

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Details on exposure:

PREPARATION OF DOSING SOLUTIONS :
On a daily basis, a sufficient amount of the test item was diluted 1:10 with purified water, to obtain a concentration of 39.8 mg/mL (stock solution). Then further independent solutions were prepared with the same vehicle from the stock solution to give the required concentrations of 0.5, 2, 6 and 8 mg/mL. Concentrations were calculated and expressed in terms of dry salt (39.8 %).

VEHICLE
- Concentration in vehicle: 0.5, 2, 6 and 8 mg/mL
- Amount of vehicle (if gavage): 10 mL/kg body weight

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

- Prior to commencement of treatment, analysis was performed to confirm that the proposed formulation procedure was acceptable (content check). Samples of the formulations prepared on Week 1 and last week were also analysed to check the concentration.
- Chemical analysis was carried out by the Analytical Chemistry Department at RTC according to a validated method (RTC Study nos. 82340, 82350 and 89720) in the range from 0.03 to 100 mg/mL in purified water.

Results: Results of all analyses were within the limits of acceptance.

Details on mating procedure:

- Impregnation procedure: cohoused
- If cohoused:
- M/F ratio per cage: 1/1; Females were paired one to one in the home cage of the male and left overnight. Vaginal smears were taken daily in the morning, from the day after pairing until a positive identification of mating was made.
- Length of cohabitation: overnight
- Further matings after two unsuccessful attempts: not applicable
- Verification of same strain and source of both sexes: no data
- Proof of pregnancy: vaginal plug / sperm in vaginal smear referred to as day 0 of pregnancy (or Day 0 post coitum)

Duration of treatment / exposure:

14 days (Days 6-19 post coitum)

Frequency of treatment:

Once daily, from Day 6 through Day 19 post coitum

Duration of test:

21 days (Days 0-20 post coitum)

No. of animals per sex per dose:

24 mated females/dose

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: The dose levels of 5, 20, 60 and 80 mg/kg bw/day were selected in agreement with the Sponsor, based on information from previous studies.
- Rationale for animal assignment: Before the beginning of the treatment period, the animals were allocated to the groups, according to a computerised stratified randomisation based on body weight recorded on Day 0 post coitum, to give approximately equal initial group mean body weights.

Examinations

Maternal examinations:

CAGE SIDE & CLINICAL OBSERVATIONS: Yes
Time schedule:
- Mortality or signs of morbidity: Twice a day throughout the study, including weekends and public holidays.
- Clinical signs: Once daily. Clinical signs for one animal were erroneously not recorded on Day 1 post coitum.

BODY WEIGHT: Yes
- Time schedule for examinations: Days 0, 3, 6, 9, 12, 15, 18 and 20 post coitum.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes
- Time schedule: Days 3, 6, 9, 12, 15, 18 and 20 post coitum, starting from Day 0 post coitum.

POST-MORTEM EXAMINATIONS: Yes
- Time schedule: On Day 20 post coitum, females were sacrificed by inhalation of carbon dioxide and were subjected to a macroscopic post-mortem examination which included the observation of all visible structures, surfaces and orifices.

OTHER:
Preservation of tissues:
- Changes were noted and the abnormalities preserved in 10% neutral buffered formalin.
- From all adult females completing the scheduled test period, liver was preserved in 10% neutral buffered formalin.

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes, , uteri or individual uterine horns without visible implantations were immersed in a 20% solution of ammonium sulphide to reveal evidence of embryonic death at very early stages of implantation
- Number of late resorptions: Yes
- Other: uterine scars, gross evaluation of placentas

Fetal examinations:

EXAMINATION OF FETUSES:
- Number of all live fetuses: Yes
- Number of dead fetuses (fetuses at term without spontaneous movements and breathing): Yes
- Live fetuses were sacrificed by intraperitoneal injection of Sodium Thiopental followed by hypothermia.
- Body weight of fetuses: Body weight of each live fetus was recorded.
- Sex of fetuses: Sex of each fetus was determined at the time of caesarean.
- External examinations: Yes; each fetus was subjected to a detailed external examination, which included the observation of all visible structures, surfaces and orifices.
- Soft tissue examinations: Yes, approximately half of the live fetuses in each litter were eviscerated and were fixed in Bouin’s solution.
- Skeletal examinations: Yes [all the remaining litters]; eviscerated and fixed in 95% (v/v) ethanol, for subsequent skeletal examination.
- Head examinations: No data

Statistics:

- For continuous variables the significance of the differences amongst group
means was assessed by Dunnett’s test or a modified t test, depending on the homogeneity of data.
- Statistical analyses of non-continuous variables were carried out by means of the Kruskal-Wallis test and intergroup differences between the control and treated groups assessed by a non-parametric version of the Williams test.
- The mean values, standard deviations and statistical analysis were calculated from actual values in the computer without rounding off.

Indices:

- Pre-implantation loss: [(Number of corpora lutea - Number of implantation sites) / Number of corpora lutea] X 100
- Post-implantation loss: [(Number of implantation sites - Number of live fetuses) / Number of implantation sites] X 100
- Total impl antation loss: [(Number of corpora lutea - Number of live fetuses) / Number of corpora lutea] X 100
- Sex ratios of the foetuses were calculated as the percentage of males per litter.
- All derived values (e.g., means, percentages, ratios) were first calculated within the litter and the group values derived as a mean of individual litter values.
- Foetal structural deviations were expressed as the percentage of affected foetuses relative to all foetuses examined per group, as well as in terms of the mean litter percentage of affected litters.

Historical control data:

No data

Results and discussion

Results: maternal animals

General toxicity (maternal animals)

Clinical signs:

no effects observed

Description (incidence and severity):

No relevant clinical signs or signs of reaction to treatment were noted in treated females.
Hairloss was observed in few females of the control and treated groups. In addition, some of these females, with the exception of those of the high dose groups, showed also scabs. Vaginal discharge was observed in one female receiving 60 mg/kg/day on Day 15 post coitum.

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Description (incidence and severity):

- No differences in body weight were noted between control and treated groups.
- On Day 9 post coitum, a decrease in body weight gain between -4% to -26% was recorded in all treated groups when compared to controls, with a statistical significance in mid-, mid-high and high dose groups.
- In addition, a decrease, between -21% to -33% in body weight gain, was noted in females receiving 60 and 80 mg/kg/day on Day 12 post coitum, in females receiving 60 mg/kg/day on Day 15 post coitum and in females receiving 5 mg/kg/day on Day 20 post coitum.
- Recovery was observed on Day 18 post coitum, where an increase in body weight gain was recorded in all treated females when compared to controls.

Terminal body weight, uterus weight and absolute weight gain of females
- No significant differences in terminal body weight and gravid uterus weight were observed in treated groups when compared to the control group. The statistically significant decrease in absolute weight gain detected in midhigh (-18%) and high dose (-13%) groups with respect to controls was not considered of toxicological relevance.

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

- The statistically significant decrease up to approximately 11%, detected on Days 12 and 15 post coitum in females receiving 60 and 80 mg/kg/day, was not considered of toxicological relevance.

Organ weight findings including organ / body weight ratios:

no effects observed

Description (incidence and severity):

No differences of toxicological relevance were noted in gravid uterus weight between treated and control groups (table 7.8.2-3)

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

Maternal necropsy findings:
- The only relevant change detected at post mortem examination was swollen and/or enlarged liver in some females dosed at 80 mg/kg/day indicative of maternal toxicity at this dose level.
- The remaining macroscopic changes, such as swollen liver in few females dosed at ≥ 20 mg/kg/day, pale area/s in the left lobe of the liver in single females dosed at 60 or 80 mg/kg/day or marked hairloss mainly noted in few females dosed at 60 mg/kg/day, could be considered incidental and not clearly treatment related.

Histopathological findings: non-neoplastic:

not examined

Other effects:

effects observed, non-treatment-related

Description (incidence and severity):

The lower absolute weight gain noted at the doses 60 (-18%) and 80 (-13%) mg/kg/day compared to the control group was not considered of toxicological relevance. The differences were likely related to the slightly higher gravid uterus weights in those 2 groups. (Table 7.8.2-3)

Maternal developmental toxicity

Number of abortions:

no effects observed

Pre- and post-implantation loss:

no effects observed

Description (incidence and severity):

No statistically significant differences were observed between groups.

Total litter losses by resorption:

no effects observed

Early or late resorptions:

no effects observed

Dead fetuses:

no effects observed

Description (incidence and severity):

The number of females with live foetuses on Day 20 post coitum was 24 in each of the control and treated groups.
One foetus was found dead in the lowest dose group.

Changes in number of pregnant:

no effects observed

Description (incidence and severity):

All females were found pregnant at necropsy.
One control female and one female receiving 5 mg/kg/day had unilateral implantation.

Effect levels (maternal animals)

Key result

Dose descriptor:

NOAEL

Effect level:

60 mg/kg bw/day

Based on:

act. ingr.

Basis for effect level:

gross pathology

Maternal abnormalities

Key result

Abnormalities:

effects observed, treatment-related

Localisation:

other: Liver

Description (incidence and severity):

4/24 females at the highest dose displayed enlarged liver, and 2/24 had swollen liver.

Results (fetuses)

Fetal body weight changes:

no effects observed

Description (incidence and severity):

mean foetal weight was not affected by treatment.

Reduction in number of live offspring:

no effects observed

Description (incidence and severity):

The mean number of viable foetuses was similar in all groups

Changes in sex ratio:

no effects observed

Changes in litter size and weights:

no effects observed

Description (incidence and severity):

Litter data were not affected by treatment: mean litter size and mean litter weight were similar in all groups

External malformations:

effects observed, non-treatment-related

Description (incidence and severity):

External observations:
- The malformation imperforation of anus was observed in one foetus of the mid-high dose group and one dead foetus was detected in the low dose group.
- A total of 11 small foetuses (<2.7 g) were seen: one out of 342 in control group, one out of 348 in low dose group, three out of 352 in mid-dose group and six out of 370 in mid-high dose group. No small foetuses were noted in the high dose group.
- All these findings were not dose-related and therefore considered incidental.

Skeletal malformations:

effects observed, non-treatment-related

Description (incidence and severity):

Skeletal and cartilage observations:
- A total of 9 foetuses showed malformations at skeletal examination: 4 in the control group, 2 in the mid-dose group, 3 in the mid-high dose group. No malformations were detected in the low and high dose groups.
- Lumbar hemivertebrae, pubis no ossification, ribs fused or displaced were the malformations detected in 4 different litters of the control group. One of these litter also showed a foetus with dextrocardia at visceral examination.
- Pubis no ossification and absence of one rib were the malformations detected in 2 different litters of the mid-dose group.
- Centra fused of a lumbar vertebrae, pubis no ossification and absence of one rib were the malformations detected in 2 different litters of the mid-high dose group. One of these females also showed a foetus with malformation at visceral examination.
- Other alterations recorded at skeletal examination were noted both in control and treated groups, with a similar incidence.
- Considering that some of these findings were observed in small foetuses (foetal weight less than 2.7 g) and were without a dose-relation, they were considered incidental and not related to treatment.

Visceral malformations:

effects observed, non-treatment-related

Description (incidence and severity):

Soft tissue observations:
- A total of 4 foetuses showed malformations at visceral examination: 1 (dextrocardia) in the control group, 2 (anophtalmia and hydrocephalia) in the low dose group and 1 (agenesis of ovaries and malpositioned uterus) in the mid-high dose group. No malformations were detected in the mid- and high dose groups.
- Due to the absence of a dose-relation and to the low incidence of malformations, variations and anomalies, all the findings detected at visceral examination were considered incidental.

Effect levels (fetuses)

Key result

Dose descriptor:

NOAEL

Effect level:

ca. 80 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: Incidental findings detected at the external, visceral and skeletal examination of foetuses from all groups with no dose-relationship.

Fetal abnormalities

Key result

Abnormalities:

effects observed, non-treatment-related

Description (incidence and severity):

Incidental findings detected at the external, visceral and skeletal examination of foetuses from all groups with no dose-relationship.

Overall developmental toxicity

Key result

Developmental effects observed:

no

Any other information on results incl. tables

MATERNAL DATA

Table 7.8.2-2: Mean maternal body weight gain (g)

Dose (mg/kg/day)	0	5	20	60	80
GD 3	7.243	6.064	7.240	7.209	6.180
GD 6	5.948	6.234	6.150	6.294	6.674
GD 9	5.816	5.555	4.650*	4.290**	4.654*
GD 12	6.948	6.266	7.191	5.328**	4.667**
GD 15	6.358	7.453	6.269	5.025*	5.267
GD 18	12.498	14.705*	14.901*	14.570	15.394**
GD 20	19.185	14.475*	17.353	17.859	18.302

 GD: gestation day; *: p<0.05; **: p<0.01

Table 7.8.2-3: Terminal body weight, uterus weight and absolute weight gain (g) - group mean data (24 females/group)

Dose (mg/kg/day)	0	5	20	60	80
Terminal body weight (g)
mean	410.50	410.82	411.64	399.50	405.05
sd	28.41	27.61	23.08	29.06	28.42
Gravid uterus weight (g)
mean	84.12	85.90	86.73	88.72	87.28
sd	18.24	16.72	8.36	9.32	10.99
Absolute weight gain (g)#
mean	83.17	82.79	82.15	67.90*	72.46*
sd	16.29	16.69	14.20	16.07	13.61

# body weight at necropsy minus gravid uterine weight, minus body weight at day 0 of pregnancy

Statistical analysis: Krukall Wallis test, or William's test if group differences are different from control at p< 0.05

*: p< 0.05

Tablea 7.8.2-4: Main macroscopic findings in females

Dose (mg/kg/day)	0	5	20	60	80
N examined	24	24	24	24	24
Liver
abnormal area(s), pale	0	0	0	1	1
Abnormal shape, swollen	0	0	3	2	2
abnormal size, enlarged	0	0	0	0	4
Uterus
unilateral implantation	1	1	0	0	0

No microscopic examination was performed in this study

Applicant's summary and conclusion

Conclusions:

There were no treatment-related effects on maternal parameters (corpora lutea, implantation sites, intra-uterine deaths) or on foetal data (live foetuses, litter or foetus weights, sex ratio or foetal development). Under the test conditions, the No Observed Adverse Effect Level (NOAEL) of cC6O4 was considered to be 60 mg/kg bw/day for maternal toxicity (based on macroscopic findings and lower absolute weight gain) and 80 mg/kg bw/day (highest tested dose level) for developmental toxicity in Sprague-Dawley rats.

Executive summary:

In a GLP-compliant prenatal developmental toxicity study performed according to OECD Guideline 414, cC604 diluted in water was administered by gavage to groups of mated female Sprague-Dawley rats (24 mated females/dose) at the dose levels of 0, 5, 20, 60 and 80 mg /kg bw/ day (in terms of dry salt (39.8 %)) from Days 6 to 19 post-coitum. Clinical signs and mortality were checked daily. Maternal body weight and food consumption were recorded approximately every 3 days. On Day 20 post-coitum, the dams were sacrificed and subjected to macroscopic examination. The gravid uterine weight, number of implantations, uterine scars, live and dead fetuses, early and late resorptions and corpora lutea were recorded. Gross evaluation of the placenta was also performed. Fetuses were sexed, weighed and examined for external, soft tissue and skeletal malformations.

All mated animals were pregnant. No mortality was observed. No relevant clinical signs or signs of reaction to treatment were noted in treated females. No differences of toxicological relevance were noted in body weight, food consumption, gravid uterus weight and litter data of treated females when compared to controls. Swollen and/or enlarged liver was detected at macroscopic examination in some females dosed at 80 mg/kg/day, indicating the presence of a maternal toxicity at this dose level.

Due to the absence of a dose-relation, the findings detected at the external, visceral and skeletal examination of foetuses from all groups were considered to be incidental.

On the basis of the results obtained in this study, the dosage of 60 mg/kg bw/day was considered to be the NOAEL (No Observed Adverse Effect Level) for maternal toxicity. The NOAEL for developmental toxicity was considered to be 80 mg/kg bw/day.

This study was considered as acceptable as it satisfied the main criteria of the OECD guideline.