Hydroxy(2-methylprop-2-enoato-O)zinc

Endpoint summary

Description of key information

- Hydroxy(2-methylprop-2-enoato-O)zinc: LD50 > 2000 mg/kg bw in rats
- Zinc methacrylate: LC50 > 5.32 mg/L for 4 hr in rats

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

01 August - 20 September 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP study conducted in compliance with OECD Guideline 423 with a minor deviation: the temperature recorded in the animal room was sometimes outside of the target ranges

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

Deviations:

yes

Remarks:

the temperature recorded in the animal room was sometimes outside of the target ranges

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Limit test:

no

Species:

rat

Strain:

Sprague-Dawley

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Janvier, Le Genest-Saint-Isle, France
- Age at study initiation: Approximately 8 weeks
- Weight at study initiation: 210 g (range: 194-228 g)
- Fasting period before study: Animals were fasted overnight before treatment. Food was given approximately 4 h after administration of the test item.
- Housing: Animals from the same group were housed by three in polycarbonate cages with stainless steel lids (Tecniplast 2154, 940 cm²).
- Diet: SSNIFF R/M-H pelleted maintenance diet (SSNIFF Spezialdiäten GmbH, Soest, Germany), ad libitum
- Water: Tap water (filtered with a 0.22 µm filter), ad libitum
- Acclimation period: 5 or 8 days

ENVIRONMENTAL CONDITIONS
- Temperature: 22 ± 2 °C
- Humidity: 50 ± 20 %
- Air changes: Approximately 12 cycles/h of filtered, non-recycled air
- Photoperiod: 12 h dark / 12 h light

Route of administration:

oral: gavage

Vehicle:

other: 0.5 % methylcellulose aqueous

Details on oral exposure:

VEHICLE
- Concentration in vehicle: 30 and 200 mg/mL
- Justification for choice of vehicle: As heterogeneous suspension at 200 mg/mL was obtained with drinking water treated by reverse osmosis, the test item was tested with 0.5% methylcellulose aqueous solution. A homogenous suspension was obtained at the concentration of 200 mg/mL in 0.5% methylcellulose aqueous solution. Therefore, 0.5 % methylcellulose aqueous was selected as vehicle.
- Lot/batch no. (if required): 068K0020

MAXIMUM DOSE VOLUME APPLIED: 10 mL/kg bw

DOSAGE PREPARATION:
- Test item was administered as a homogenous suspension in the vehicle. The test item was ground to a fine powder, using a mortar and pestle, and then mixed with the required quantity of vehicle. Dose formulations preparations were prepared on the day of each administration. The dose formulations were stored at room temperature and delivered to the study room in brown flasks.

CLASS METHOD (if applicable)
- Rationale for the selection of the starting dose: Since no relevant toxicity data were available for the estimation of a lethal dose-level and any existing data were taken into account by the Sponsor, the starting dose level was 300 mg/kg bw for ethical reasons.

Doses:

300 and 2000 mg/kg bw

No. of animals per sex per dose:

- First assay: 3 females/dose (300 and 2000 mg/kg bw)
- Confirmatory assay: 3 females (2000 mg/kg bw)

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing:
Clinical signs and mortality: Each animal was checked for mortality and morbidity, frequently during the hours following administration, then at least once a day until the end of the observation period, including weekends and public holidays. Each animal was observed after treatment as follows: at least once during the first 30 minutes, periodically during the first 4 h, then once a day, at approximately the same time, for the recording of clinical signs.
Bodyweight: Body weight of each animal was recorded the day of group allocation then on the day of treatment and on Days 8 and 15.
- Necropsy of survivors performed: Yes; On completion of the observation period, animals were deeply anesthetized by an intraperitoneal injection of pentobarbital sodium and euthanized by exsanguination and macroscopic examination was performed.

Statistics:

None

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Remarks on result:

other: No unscheduled deaths and no clinical signs were observed in any animals.

Mortality:

- No mortality was observed.

Clinical signs:

other: - No clinical signs were observed.

Gross pathology:

- No macroscopic abnormalities were observed at necropsy.

Other findings:

None

Table 7.2.1/1: Body weight

 

Sex	Female
Group	Historical control data	1	2	3
Dose-level (mg/kg)	0	300	2000	2000
Body weight
Day 1	219	197	211	221
Day 8	264	245	243	261
Day 15	284	260	261	276
Body weight change
Days 1-8	+44	+48	+32	+40
Days 8-15	+20	+16	+18	+16
Days 1-15	+64	+63	+50	+56

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Under the test conditions, the oral LD50 for Hydroxy(2-methylprop-2-enoato-O)zinc is higher than 2000 mg/kg bw in female rats therefore it is not classified according to the Annex VI to the Directive 67/548/EEC and the CLP Regulation (EC) N° (1272-2008).

Executive summary:

In a GLP acute oral toxicity study performed according to OECD Guideline 423, groups of 3 female Sprague Dawley [Rj Han: SD] rats were given a single oral (gavage) dose of Hydroxy(2-methylprop-2-enoato-O)zinc at 300 and 2000 mg/kg bw. Animals were then observed for mortality, clinical signs and bodyweights for 14 days and were all sacrificed for macroscopic examination.

No mortality or clinical signs were observed. When compared to laboratory historical control data, a trend to a slightly lower mean body weight gain was observed in females treated at 2000 mg/kg bw (group 2, first assay) during the first week of study. No macroscopic abnormalities were observed at study termination. In this study, the oral LD50 of the test item was therefore considered to be higher than 2000 mg/kg bw.

Under the test conditions, the oral LD50 for Hydroxy(2-methylprop-2-enoato-O)zinc is higher than 2000 mg/kg bw in female rats. Therefore, according to the Annex VI to the Directive 67/548/EEC and the CLP Regulation (EC) N° (1272-2008), it is not classified for acute oral toxicity.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Quality of whole database:

GLP-compliant study with a Klimish 1

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

09-31 October 2012

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP study conducted according to OECD 436 Guideline with deviation: one sample was greater than 20 % of the mean achieved atmosphere concentration.

Reason / purpose for cross-reference:

reference to same study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

OECD Guideline 436 (Acute Inhalation Toxicity: Acute Toxic Class Method)

Deviations:

yes

Remarks:

one sample was greater than 20 % of the mean achieved atmosphere concentration

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Limit test:

yes

Species:

rat

Strain:

other: RccHan : WIST strain

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan Laboratories UK Ltd, Oxon, UK.
- Age at study initiation: Approximately 8-12 weeks
- Weight at study initiation: 200-350 g
- Housing: Animals were housed in groups of up to three by sex in solid-floor polypropylene cages with stainless steel lids, furnished with softwood flakes.
- Diet: Food (Harlan 2014C Rodent Diet, Harlan Laboratories UK Ltd, Oxon, UK), ad libitum
- Water: Mains drinking water, ad libitum
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature: 19-25 °C
- Humidity: 30-70 %
- Air changes: 15/h
- Photoperiod: 12 h dark / 12 h light

Route of administration:

inhalation: dust

Type of inhalation exposure:

nose only

Vehicle:

air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: SAG 410 Solid Aerosol Generator (TOPAS GmbH, Dresden, Germany)
- Exposure chamber volume: Approximately 30 litres (dimensions: 28 cm diameter x 50 cm high)
- Method of holding animals in test chamber: Each rat was individually held in a tapered, polycarbonate restraining tube fitted onto a single tier of the exposure chamber and sealed by means of a rubber ‘O’ ring.
- Source and rate of air: Compressed air at 60 L/min providing 120 air changes per hour.
- Method of particle size determination: Particle size of the generated atmosphere inside the exposure chamber was determined three times during the exposure period using a Marple Personal Cascade Impactor (Westech IS Ltd, Beds., UK).
- Treatment of exhaust air: The extract from the exposure chamber passed through a ‘scrubber’ trap and was connected with a high efficiency filter to a metered exhaust system.
- Temperature and humidity in air chamber: 19-20 ºC and 56-68 %; Temperature and relative humidity inside the exposure chamber were measured by an electronic thermometer/humidity meter (Hanna Instruments Ltd, Beds., UK) located in a vacant port in the animals’ breathing zone of the chamber and recorded every thirty minutes throughout the four-hour exposure period.

TEST ATMOSPHERE
- Samples taken from breathing zone: Yes

VEHICLE
- In order to facilitate aerosolisation and reduce particle size, the test item was ground using a small amount of diethyl ether in a Retsch Planetary Ball Mill (Retsch (UK) Ltd, Leeds, UK) the solvent was removed via evaporation prior to use.

TEST ATMOSPHERE (if not tabulated)
- Particle size distribution: See table 7.2.2/1
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): 2.69 / 2.66

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

5 mg/mL (target concentration)

No. of animals per sex per dose:

3

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations: All animals were observed for clinical signs at hourly intervals during exposure, immediately on removal from the restraining tubes at the end of exposure, one hour after termination of exposure and subsequently once daily for up to 14 days.
- Frequency of weighing: Individual bodyweights were recorded on arrival, prior to treatment on the day of exposure and on Days 1, 3, 7 and 14 or at death.
- Necropsy of survivors performed: Yes, All animals, including the one that died during the study, were subjected to a full external and internal examination, and any macroscopic abnormalities were recorded. The respiratory tract was subjected to a detailed macroscopic examination for signs of irritancy or local toxicity.

Statistics:

None

Preliminary study:

Not applicable

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5.32 mg/L air

Based on:

test mat.

Exp. duration:

4 h

Remarks on result:

other: No mortality was observed in males and 1/3 female died during the study

Mortality:

No mortality was observed in males and 1/3 female died during the study.

Clinical signs:

other: - Upon removal from the chamber, all animals exhibited increased respiratory rate and ataxia and occasional instances of noisy respiration, which remained one hour post removal. - One day post exposure, all animals exhibited hunched posture, pilo-erection

Body weight:

- All animals exhibited bodyweight losses on the first day post-exposure.
- All animals exhibited bodyweight gains during the remainder of the recovery period, with the exception of one surviving female animal which showed no bodyweight gain from Days 1 to 3 post-exposure.

Gross pathology:

- No macroscopic abnormalities were detected at necropsy amongst the animals that survived until the end of the fourteen day recovery period.
- Macroscopic abnormalities such as dark patches in the lungs and gaseous distension in stomach were noted at necropsy in the animal that died during the course of the study.

Other findings:

None

Table 7.2.2/1: Particle Size Distribution

Cascade Impactor Data

Impactor Stage Number	Cut Point (μm)	Amount Collected (mg) per Sample Number			Mean Amount Collected (mg)
		1	2	3
3	8.6	0.27	0.14	0.16	0.19
4	5.5	0.60	0.62	0.46	0.56
5	3.8	0.65	0.80	0.62	0.69
6	1.7	0.62	1.03	0.91	0.85
7	0.86	0.36	0.20	0.19	0.25
8	0.41	0.19	0.02	0.10	0.10
Back-up Filter	<0.41	0.22	0.23	0.23	0.23
Total Mean Amount of Test Item Collected					2.87

 

Calculation

Cut Point (μm)	Log10 Cut Point	Mean Cumulative Amount Less Than Cut Point
		mg	%	Probit
8.6	0.935	2.68	93.4	6.51
5.5	0.740	2.12	73.9	5.64
3.8	0.780	1.43	49.8	5.00
1.7	0.230	0.58	20.2	4.17
0.86	-0.066	0.33	11.5	3.80
0.41	-0.387	0.23	8.01	3.60

 

Results

 

Mean Mass Median Aerodynamic Diameter (MMAD) = 2.69 μm

Geometric Standard Deviation (GSD) = 2.66

Predicted amount less than 4 μm = 65.8%

 

Table 7.2.2/2: Mortality Data

Mean Achieved Atmosphere Concentration (mg/L)	Sex	Deaths During Exposure	Deaths Post Exposure (1 Hour)	Deaths During Day of Observation								Total Deaths
				1	2	3	4	5	6	7	8-14
5.32	Male	0	0	0	0	0	0	0	0	0	0	1/6
	Female	0	0	0	1	0	0	0	0	0	0

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Under the test conditions, the inhalation LC50 for Zinc dimethacrylate is higher than 5.32 mg/mL for 4 h in rats. It is therefore not classified according to the Annex VI to the Directive 67/548/EEC and the CLP Regulation (EC) N° (1272-2008).

Executive summary:

In a GLP-compliant acute inhalation toxicity study performed according to OECD Guideline 436, groups (3/sex/dose) of RccHan : WIST strain rats were exposed (nose only) to dust atmosphere of Zinc dimethacrylate at the concentration of 5.32 mg/mL (mean achieved) for 4 h. Animals were observed for mortality and signs of sensory irritation, airflow limitation and pulmonary irritation during the exposure period and continued the observation up to 14 days and necropsy was performed.

No mortality was observed in males and 1/3 female died on day 2. Common abnormalities noted during the study included increased respiratory rate, ataxia, hunched posture, pilo-erection, red/brown staining around the eyes and/or snout and wet fur. Frequent occurrences of sneezing and occasional instances of decreased respiratory rate and noisy respiration were also noted on the first days post exposure. The surviving animals recovered to appear normal from Days 8 to 9 post-exposure. All animals exhibited bodyweight losses on the first day post-exposure. All animals exhibited bodyweight gains during the remainder of the recovery period, with the exception of one surviving female animal which showed no bodyweight gain from Days 1 to 3 post-exposure. No macroscopic abnormalities were detected at necropsy amongst the animals that survived until the end of the 14 day recovery period. Macroscopic abnormalities such as dark patches in the lungs and gaseous distension in stomach were noted at necropsy in the animal that died during the course of the study. In this study, the combined inhalation LC50 of Zinc dimethacrylate was considered to be higher than 5.32 mg/mL for 4 h.

 

Under the test conditions, Zinc dimethacrylate inhalation LC50 is higher than 5.32 mg/mL for 4 h in rats, and is therefore not classified according to the Annex VI to the Directive 67/548/EEC and the CLP Regulation (EC) N° (1272-2008).

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LC50

Value:

5 320 mg/m³ air

Quality of whole database:

GLP-compliant study with a Klimish 1

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

In a GLP-compliant acute oral toxicity study performed according to OECD Guideline 423 in female Sprague Dawley rats, a single oral (gavage) dose of 300 mg/kg bw of Hydroxy(2-methylprop-2-enoato-O)zinc did not induce any mortality or clinical signs. Due to these results, a second group of animals received a single oral dose of 2000 mg/kg bw. No mortality or clinical signs were observed, so a third group of animals received a single oral (gavage) dose of 2000 mg/kg bw. Again, no mortality and no clinical signs were observed, and no findings were made during the macroscopic examination at study termination. Thus, the LD50 of Hydroxy(2 -methylprop-2 -enoato-O)zinc is higher than 2000 mg/kg bw.

In a GLP-compliant acute inhalation toxicity study performed according to OECD Guideline 436 in RccHan : WIST rats, 3 animals/sex were exposed (nose only) to a dust atmosphere of Zinc methacrylate (a Hydroxy(2 -methylprop-2 -enoato-O)zinc analogue) at the concentration of 5.32 mg/L (mean achieved) for 4 hr. One female was found dead on Day 2 post-dosing. All the other animals survived. Reversible common abnormalities after inhalation exposure to dust (increased respiratory rate, ataxia, hunched posture, pilo-erection, red/brown staining around the eyes) with frequent occurences of sneezing were observed on the first days post exposure and were totally reversed within 8 -9 days. Body weight loss was also observed on the first day post-exposure but was reversed within 24 hr with the exception of one surviving female that did not show any weight gain from Day 1 to 3 post exposure. No macroscopic abnormalities were detected at necropsy amongst the animals that survived until the end of the 14 day recovery period. Macroscopic abnormalities such as dark patches in the lungs and gaseous distension in stomach were noted at necropsy in the animal that died during the course of the study. Therefore, Zinc methacrylate (a Hydroxy(2 -methylprop-2 -enoato-O)zinc analogue) LC50 was considered to be higher than 5.32 mg/L for 4 h.

As the structural analogue of Hydroxy(2 -methylprop-2 -enoato-O)zinc show a LC50 > 5.32 mg/L for 4 hr, Hydroxy(2 -methylprop-2 -enoato-O)zinc is also expected to be higher than 5.32 mg/L for 4 h.

Justification for selection of acute toxicity – oral endpoint
Only one study available

Justification for selection of acute toxicity – inhalation endpoint
Only one study available

Justification for selection of acute toxicity – dermal endpoint
No study was available and it was not necessary to provide one because acute oral toxicity was studied by two other routes of administration. Acute toxicity studies were provided for the oral and inhalation routes and showed no acute toxic effects. Also, in an in vitro dermal irritation/corrosion study,Hydroxy(2-Methylprop-2-enoato-O)Zinc did not show any irritation/corrosion properties. Therefore, it is not expected to have acute toxicological properties via the dermal route. Thus, no further study for acute dermal toxicity is deemed necessary.

Justification for classification or non-classification

As Hydroxy(2 -methylprop-2 -enoato-O)zinc oral LD50 was higher than 2000 mg/kg bw/day in a GLP-compliant acute toxicity study performed according to OECD Guideline 423, it should not be classified for acute oral toxicity, according to the Annex VI to the Directive 67/548/EEC and to the CLP Regulation (EC) No 1272/2008.

As zinc methacrylate, a Hydroxy(2 -methylprop-2 -enoato-O)zinc analogue, LC50 is higher than 5.32 mg/L for 4 h and as Hydroxy(2 -methylrprop-2 -enoato-O)zinc oral LD50 is higher than 2000 mg/kg bw, Hydroxy(2 -methylprop-2 -enoato-O)zinc LC50 is expected to be higher than 5.32 mg/L for 4 h and should therefore not be classified for acute inhalation toxicity, according to the Annex VI to the Directive 67/548/EEC and to the CLP Regulation (EC) No 1272/2008.

As Hydroxy(2 -methylprop-2 -enoato-O)zinc has a very low acute toxicity by the oral and inhalation routes, it is not expected to be toxic by the dermal route. It should therefore not be classified for dermal toxicity according to the Annex VI to the Directive 67/548/EEC and to the CLP Regulation (EC) No 1272/2008.