5H-1,2-oxathiole 2,2-dioxide

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Gene mutation (Bacterial Reverse Mutation Assay/Ames test): the substance 1,3-Propenesultone was considered to be mutagenic in S. typhimurium TA98, TA100, TA1535, TA1537 and E. coli WP2 uvrA in the presence and absence of Delor 106-induced rat liver S9 metabolic activation. (OECD 471/GLP).

Link to relevant study records

Reference

Endpoint:

in vitro gene mutation study in bacteria

Type of information:

experimental study

Adequacy of study:

key study

Study period:

20/06/2019 - 08-08-2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch number of test material: Shijiazhuang Suntec-chem Co.,Ltd; 190403
- Expiration date of the lot/batch: Apr 10, 2020
- Purity: 99.29%

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Store at room temperature. Keep container tightly closed in a dry and well-ventilated place. Containers which are opened must be carefully resealed.
- Storage and handling during the study: The sample of test item has been stored in a glass vial, at room temperature, in dark.

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98, TA 100 and E. coli WP2

Metabolic activation:

with and without

Metabolic activation system:

Type and composition of metabolic activation system:
- source of S9 : rat liver homogenate and mixture of cofactors
- method of preparation of S9 mix: The liver homogenate was prepared from Wistar male rats weighing approximately 200 g, previously induced with Delor 106 (mixture of polychlorinated biphenyls). Delor 106 was diluted with olive oil to a concentration of 200 mg•mL-1, and each rat was administered a single intraperitoneal injection of 500 mg/kg 5 days before S9 preparation.
The S9 was prepared according to the methods described by Maron and Ames (1). The liver was removed from each animal and washed in ice cold 0.15M KCl. The livers washed were mixed with another 0.15 M KCl (3 mL.g-1 wet liver) homogenized in a grinder, and the tissue suspension was centrifuged for 10 min at 9000 g. Aliquots of the supernatant (S9) were stored in plastic tubes using sterile technique at a temperature below 70 °C. Cofactors (NADP and glucoso-6-phosphate) were dissolved in buffer.
- concentration or volume of S9 mix and S9 in the final culture medium: Volume of 20 μL (3.8 % of S9 in S9 mix) of S9 is used for positive controls in all strains (reason – to keep constant conditions for database of historical values).
Volume of 30 μL(5.7% of S9 in S9 mix) of S9 was used for test item, solvent and negative control plates in the first experiments.
- quality controls of S9 (e.g., enzymatic activity, sterility, metabolic capability) non-toxicity, non-mutagenicity and sterility of vehiculum

Test concentrations with justification for top dose:

Preliminary test: 10, 100, 500, 1000, 2500 and 5000 μg per plate
Main test: 50, 150, 500, 1500 and 5000 μg per plate

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO

- Justification for choice of solvent/vehicle: The test item was dissolved in water for injection and in dimethyl sulfoxide in the highest recommended concentration 5000 μg per plate. The test item was partially soluble in water; the entire test item was not dissolved even the next day. The entire test item was dissolved almost immediately in DMSO. So DMSO was used for mutagenicity testing.

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

9-aminoacridine

sodium azide

other: 4-nitro-o-phenylenediamine (NPD): TA 98 - S9 2-aminofluorene (2-AF): TA 100 and TA 98 + S9 2-aminoanthracene (2-AA): TA 1535, TA 1537, E.coli + S9 M-methyl-N´-nitro-N-nitrosoguanidine (MNNG): E. coli - S9

Details on test system and experimental conditions:

NUMBER OF REPLICATIONS:
- Number of cultures per concentration: Ttriplicate plating
- Number of independent experiments: 1

METHOD OF TREATMENT/ EXPOSURE:
- Test substance in agar (plate incorporation)

TREATMENT AND HARVEST SCHEDULE:
- Exposure duration/duration of treatment: 72 h

METHODS FOR MEASUREMENT OF CYTOTOXICITY
- Method.: background growth inhibition

Evaluation criteria:

The main criterion used for the evaluation of reversion results was a modified two-fold increase rule, which is compatible with the application of statistical methods (2, 3). Per this rule, the result is positive if a reproducible dose-response effect occurs and/or a doubling of the ratio Rt/Rc is reached (Rt – number of revertants at tested dose, Rc – number of revertants of the solvent control).

An increase is considered as ”biologically relevant“:

- if the number of reversions is at least twice as high as that in the solvent control for the strains having spontaneous reversion >10;
- if the number of reversions is at least three times as high as that in the solvent control for the strains having spontaneous reversion ≤10;

A test item producing neither a dose-related increase in the number of revertants nor a reproducible biologically relevant positive response at any of the dose groups is considered to be non-mutagenic in this system.

Statistics:

Mean and SD of triplicate plates

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Species / strain:

E. coli WP2 uvr A

Metabolic activation:

with and without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

no cytotoxicity nor precipitates, but tested up to recommended limit concentrations

Vehicle controls validity:

valid

Untreated negative controls validity:

not examined

True negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation and time of the determination: No precipitation

RANGE-FINDING/SCREENING STUDIES (if applicable):
The test item was dissolved in DMSO up to the highest concentration recommended in the OECD TG 471 guideline – 5000 μg per 0.1 millilitre (plate). For the cytotoxicity experiment, the highest concentration was diluted to the other 5 concentrations within the range of 3 orders of magnitude. The concentration series was tested for toxicity in strain TA 98 without metabolic activation. Neither cytotoxicity nor precipitation was observed at any concentration. In line with the toxicity test results, the highest concentration selected was 5000 μg per plate. A dilution factor between 2 and √10 was used with a resulting concentration range of 50, 150, 500, 1500 and 5000 ug per plate.


STUDY RESULTS
- Concurrent vehicle negative and positive control data : All controls (solvent and negative) gave the appropriate responses and deviations were acceptable and did not affect the study results.

For all test methods and criteria for data analysis and interpretation:
- Concentration-response relationship where possible : A dose-effect relationship was evident in all experiments
- Statistical analysis: according to OECD TG 471, the biological relevance is the criterion for the interpretation of results, and a statistical evaluation of the results is not necessary.

Ames test:
- Signs of toxicity: No cytotoxicity was observed at any concentration.
- Individual plate counts: Triplicate values for all strains with and without S9 are in Tables 1-5.
- Mean number of revertant colonies per plate and standard deviation: Mean and SD values for all strains with and without S9 are in Tables 1-5.

HISTORICAL CONTROL DATA (with ranges, means and standard deviation, and 95% control limits for the distribution as well as the number of data)
- Positive historical control data: refer to Table A
- Negative (solvent/vehicle) historical control data: refer to Table A

TableA: Current historical ranges  

Control Strain	Spont.rev.	DMSO	PC - S9	PC + S9	Number of CFU/mL
S.t. TA 100	69-177 (859)	66-170 (546)	341-597 (44)	875-3015 (40)	4.56*10^9
S.t. TA 1535	9-29 (669)	11-27 (422)	434-730 (40)	64-420 (38)	3.10*10^9
S.t. TA 98	13-49 (915)	13-45 (567)	1310-3346 (42)	1904-5024 (42)	7.60*10^8
S.t. TA 1537	5-21 (710)	4-20 (441)	1419-4139 (38)	5-405 (31)	1.67*10^9
E.c. WP2 uvrA	11-51 (691)	8-44 (397)	479-1919 (39)	216-1056$ (12)	1.36*10^9

Conclusions:

In a reverse bacteria mutation study (Ames test), the test item, 1,3-Propenesultone, was mutagenic in all strains in experiments with and without metabolic activation. Based on this result, the test substance is considered mutagenic.

Executive summary:

In a reverse gene mutation assay in bacteria (152-19-12), strains of S. typhimurium strains TA98, TA100, TA1535, TA1537 and E. coli WP2 uvrA were exposed to 1,3-Propenesultone (99.92%) in DMSO at concentrations of 50, 150, 500, 1500 and 5000 μg/plate (plate incorporation) with and without metabolic activation (Delor 106-induced rat liver S9).

No cytotoxicity or precipitation was observed at any dose. The positive controls induced the appropriate responses in the corresponding strains. The mutagenic response induced by the test item was high with and without metabolic activation in S. typhimurium TA100, S. typhimurium TA1535 (> 2 fold in both starting from the lowest concentration) and E. coli WP2 uvrA (>2 fold starting from 150 µg per plate). Mutagenic response was only apparent at high doses with and without metabolic activation in S. typhimurium TA98 (> 2 fold in starting from 1500 µg per plate) and S. typhimurium TA1537 (> 2 fold at 5000 µg per plate). All 5 strains were considered positive in the plate incorporation assay so a second mutagenicity test (pre-incubation method) was not performed. Under the conditions of this study, the test substance, 1,3-Propenesultone, is considered mutagenic.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (positive)

Genetic toxicity in vivo

Description of key information

Cytogenicity (mammalian erythrocyte micronucleus test): 1,3-Propenesultone was predicted to be positive in an in vivo mouse micronucleus assay (Equivalent or similar to OECD 474), based on a read-across study to 1,3-Propanesultone (CAS No. 1120-71-4).

Link to relevant study records

Reference

Reference 1

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Similar to OECD 474; read-across data

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

GLP compliance:

not specified

Type of assay:

mammalian erythrocyte micronucleus test

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Wako Pure Chemical Industries, Ltd., Osaka, Japan; WDM4950
- Purity: >97%

Species:

mouse

Strain:

CD-1

Sex:

male

Details on test animals or test system and environmental conditions:

Mice were given commercial pellets and water ad libitum throughout the acclimatization and experimental periods.

Route of administration:

intraperitoneal

Vehicle:

- Vehicle(s)/solvent(s) used: Saline

Duration of treatment / exposure:

2 IP injections, 24 hrs apart

Frequency of treatment:

Twice (24 hrs apart)

Post exposure period:

24, 48, 72 hrs

Dose / conc.:

9 mg/kg bw/day (nominal)

Dose / conc.:

18 mg/kg bw/day (nominal)

Dose / conc.:

36 mg/kg bw/day (nominal)

Dose / conc.:

72 mg/kg bw/day (nominal)

No. of animals per sex per dose:

6 males

Control animals:

yes, concurrent no treatment

Positive control(s):

- Mitomycin C
- Justification for choice of positive control(s):
- Route of administration: single IP injection; sampled at 48 hrs
- Doses / concentrations: 0.5 mg/kg

Tissues and cell types examined:

Peripheral blood reticulocytes

Details of tissue and slide preparation:

CRITERIA FOR DOSE SELECTION: The highest dose was fixed by the preliminary dose-finding test, and the micronucleus assay was performed at three levels – the highest dose and 1/2 and 1/ 4 of the highest dose. The highest dose was based on mortality.

METHOD OF ANALYSIS: Micronucleated polychromatic erythrocyte and micronucleated reticulocyte frequencies were based on the observation of at least 1000 polychromatic erythrocytes or reticulocytes per animal.

Evaluation criteria:

An expert committee evaluated each chemical considering the judgement by the investigators who performed the experiment, p-values, reproducibility, magnitude of response and biological significance. Although biological significance is difficult to judge, we took into account dose-response relationships, the kinetics of micronucleus appearance, the historical control levels when available, and the absolute magnitude of the response.

Statistics:

Pair-wise comparisons were made between the 0 hr sampling data and later sampling data. When the control data were acceptable, the increase in micronucleus frequency against the concurrent negative control data was evaluated using a conditional binomial test and the dose-response relationship was evaluated using the Cochran-Armitage trend test. When these were both significant, the data was declared positive. If neither step showed significance, the data was judged negative. All other cases were called inconclusive.

Sex:

male

Genotoxicity:

positive

Toxicity:

not specified

Remarks:

LD50 (MTD) = 290 mg/kg bw

Vehicle controls validity:

not specified

Negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

RESULTS OF DEFINITIVE STUDY
- Induction of micronuclei (for Micronucleus assay): There was a statistically significant increase (p<0.05) in micronucleated cells treated with 36 and 72 mg/kg bw 1,3-Propanesultone at 24, 48 and 72 hrs (Table 1)
- Statistical evaluation: The results of the Cochran-Armitage trend tests were all 0.000.

Table 1: Micronucleus assay results

% of MNPCE or MNRET (after the final treatment)
Dose	0 h	24 h		48 h		72 h
mg/kg bw	mean±SD	mean±SD	p	mean±SD	p	mean±SD	p
9	0.08± 0.04	0.17± 0.10	0.151	0.10± 0.13	0.500	0.08± 0.10	0.623
18	0.10± 0.11	0.23± 0.10	0.058	0.10± 0.11	0.613	0.07± 0.05	0.828
36	0.12± 0.08	0.87± 0.53	0.000	0.63± 0.16	0.000	0.28± 0.16	0.032
72	0.10± 0.09	1.92± 0.99	0.000	1.68± 0.50	0.000	0.27± 0.14	0.026

p = value of pairwise comparisons. The results of the Cochran-Armitage trend tests were all 0.000.

Conclusions:

In an in vivo micronucleus assay in male CD-1 mice, there was a statistically significant increase in micronucleated cells treated with 36 and 72 mg/kg bw 1,3-Propanesultone at 24, 48 and 72 hrs.

Executive summary:

In a CD-1 mouse peripheral blood micronucleus assay (Morita et al., 1997), groups of 6 male mice were treated by IP injection with 1,3-Propanesultone (>97%) in saline at doses of 9, 18, 36 and 72 mg/kg bw/day. A peripheral blood sample was taken from each animal immediately before treatment (0 hrs; control) and then the animals were dosed twice (0, 24 hrs) and peripheral blood was sampled at 24, 48 and 72 hrs. The positive control was Mitomycin C (0.50 mg/kg bw). Micronucleated polychromatic erythrocyte and micronucleated reticulocyte frequencies were based on the observation of at least 1000 polychromatic erythrocytes or reticulocytes per animal.

There was a statistically significant increase (p<0.05) in micronucleated cells treated with 36 and 72 mg/kg bw 1,3-Propanesultone at 24, 48 and 72 hrs. The results of the Cochran-Armitage trend tests were all 0.000. Therefore, 1,3-Propanesultone induced micronucleated reticulocytes in male CD-1 mice by double intraperitoneal treatments starting at relatively low doses.

Reference 2

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Type of information:

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

Adequacy of study:

key study

Justification for type of information:

Read-across justification attached below.

Reason / purpose for cross-reference:

read-across source

Sex:

male

Genotoxicity:

positive

Toxicity:

not specified

Remarks:

LD50 (MTD) = 290 mg/kg bw

Vehicle controls validity:

not specified

Negative controls validity:

valid

Positive controls validity:

valid

Conclusions:

In an in vivo micronucleus assay in male CD-1 mice, there was a statistically significant increase in micronucleated cells treated with 36 and 72 mg/kg bw 1,3-Propanesultone at 24, 48 and 72 hrs. 1,3-Propenesultone is also predicted to be positive in the assay.

Reference 3

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Similar to OECD 474; read-across data; IARC reviewed

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

GLP compliance:

not specified

Type of assay:

mammalian erythrocyte micronucleus test

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source of test material: Sigma Chemical

Species:

rat

Strain:

Sprague-Dawley

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratory, Wilmington, MA
- Age at study initiation: 6 weeks of age.
- Assigned to test groups randomly: Yes
- Housing: Animals were group housed
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 1 week

Route of administration:

intraperitoneal

Vehicle:

Propane sultone is water soluble and was prepared in 0.9% saline

Details on exposure:

Vehicle control and gtest item were delivered in a volume of 10 ml/kg bw

Duration of treatment / exposure:

0 hrs, 24 rhs

Frequency of treatment:

Two IP injections, 24 hrs apart

Post exposure period:

Blood samples were obtained 24 hrs after the last dose.

Dose / conc.:

12.5 mg/kg bw/day (nominal)

Dose / conc.:

25 mg/kg bw/day (nominal)

Dose / conc.:

50 mg/kg bw/day (nominal)

No. of animals per sex per dose:

5 per group

Control animals:

yes, concurrent vehicle

Positive control(s):

Ethylmethanesulphonate;
- Route of administration: IP
- Doses / concentrations:100, 200 or 300 mg/kg bw in 0.9% saline

Tissues and cell types examined:

Blood

Details of tissue and slide preparation:

DETAILS OF SLIDE PREPARATION: Blood was collected 24 or 48 h after dosing and prepared for microscopic inspection according to the AO supravital staining method. Acridine orange coated slides were prepared by homogeneously spreading a 1 mg AO/ml distilled water solution onto preheated glass slides. At the time of bleeding, 7.5 ml of blood was obtained directly from the tail vein of each rat and applied to AO-coated slides. The slides were covered with 20x50 mm coverslips, placed into a slide box, wrapped in a plastic bag and stored at -70C.

METHOD OF ANALYSIS: The acridine orange stained cells were coded and analyzed for the presence of MN using an Olympus BH2 fluorescent microscope.

Evaluation criteria:

The frequencies of micronucleated peripheral blood reticulocytes were recorded based on the analysis of 1000 Type I and Type II RETs (youngest immature)

Statistics:

Mean and SD; one-tailed t-test (p≤0.05; p≤0.0001)

Sex:

male

Genotoxicity:

positive

Toxicity:

not specified

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

valid

Additional information on results:

RESULTS OF DEFINITIVE STUDY
- Induction of micronuclei (for Micronucleus assay): There was a dose-dependent increase in the frequency of micronucleated reticulocytes 24 hours after dosing compared to vehicle controls
- Statistical evaluation: There was a statistically significant response (p≤0.05) at all dose levels.

Conclusions:

In an in vivo micronucleus assay in male Sprague Dawley rats, there was a statistically significant increase in micronucleated cells treated with 12.5, 25 and 50 mg/kg bw 1,3-Propanesultone at 24 hrs.

Executive summary:

In a Sprague Dawley peripheral blood micronucleus assay (Torous et al., 2000), groups of 5 male rats were treated by IP injection with 1,3 -Propanesultone in 0.9% saline at doses of 12.5, 25 and 50 mg/kg bw/day. Animals were dosed twice (0, 24 hrs) and peripheral blood was sampled at 24 hrs after the last dose. The positive control was Ethylmethanesulphonate (100, 200 or 300 mg/kg bw/day). The frequencies of micronucleated peripheral blood reticulocytes were recorded based on the analysis of 1000 Type I and Type II (youngest immature) reticulocytes.

There was a dose-dependent increase in the frequency of micronucleated reticulocytes 24 hours after dosing, compared to vehicle controls. There was a statistically significant response (p≤0.05) at all dose levels. Therefore, 1,3-Propanesultone induced micronucleated reticulocytes in male Sprague Dawley rats by double intraperitoneal treatments starting at relatively low doses.

Reference 4

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Type of information:

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

Adequacy of study:

supporting study

Justification for type of information:

Read-across justification attached below.

Reason / purpose for cross-reference:

read-across source

Sex:

male

Genotoxicity:

positive

Toxicity:

not specified

Vehicle controls validity:

valid

Negative controls validity:

not examined

Positive controls validity:

valid

Conclusions:

In an in vivo micronucleus assay in male Sprague Dawley rats, there was a statistically significant increase in micronucleated cells treated with 12.5, 25 and 50 mg/kg bw 1,3-Propanesultone at 24 hrs. 1,3-Propenesultone is also predicted to be positive in this assay.

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Gene mutation (Bacterial Reverse Mutation Assay/Ames test)

There is one gene mutation study (Bacterial Reverse Mutation Assay/Ames test) with 1,3-Propenesultone available.

In a reverse gene mutation assay in bacteria (OECD 471/GLP), strains of S. typhimurium strains TA98, TA100, TA1535, TA1537 and E. coli WP2 uvrA were exposed to 1,3-Propenesultone (99.92%) in DMSO at concentrations of 50, 150, 500, 1500 and 5000 μg/plate (plate incorporation) with and without metabolic activation (Delor 106-induced rat liver S9). No cytotoxicity or precipitation was observed at any dose. The positive controls induced the appropriate responses in the corresponding strains. The mutagenic response induced by the test item was high with and without metabolic activation in S. typhimurium TA100, S. typhimurium TA1535 (> 2 fold in both starting from the lowest concentration) and E. coli WP2 uvrA (>2 fold starting from 150 µg per plate). Mutagenic response was only apparent at high doses with and without metabolic activation in S. typhimurium TA98 (> 2 fold in starting from 1500 µg per plate) and S. typhimurium TA1537 (> 2 fold at 5000 µg per plate). All 5 strains were considered positive in the plate incorporation assay so a second mutagenicity test (pre-incubation method) was not performed. Under the conditions of this study, the test substance, 1,3-Propenesultone, is considered mutagenic.

Cytogenicity (mammalian erythrocyte micronucleus test)

There are no in vivo cytogenicity (mammalian erythrocyte micronucleus test) studies available with 1,3-Propenesultone. Read-across was performed to 1,3- Propanesultone (CAS No. 1120-71-4). Two in vivo cytogenicity (mammalian erythrocyte micronucleus test) studies are available with 1,3 -Propanesultone. They key study was selected as the report contained details on the high purity of the chemical used.

In a CD-1 mouse peripheral blood micronucleus key study (equivalent or similar to OECD 474; Morita et al., 1997), groups of 6 male mice were treated by IP injection with 1,3,-Propanesultone (>97%) in saline at doses of 9, 18, 36 and 72 mg/kg bw/day. A peripheral blood sample was taken from each animal immediately before treatment (0 hrs; control) and then the animals were dosed twice (0, 24 hrs) and peripheral blood was sampled at 24, 48 and 72 hrs. The positive control was Mitomycin C (0.50 mg/kg bw). Micronucleated polychromatic erythrocyte and micronucleated reticulocyte frequencies were based on the observation of at least 1000 polychromatic erythrocytes or reticulocytes per animal. There was a statistically significant increase (p<0.05) in micronucleated cells treated with 36 and 72 mg/kg bw 1,3-Propanesultone at 24, 48 and 72 hrs. The results of the Cochran-Armitage trend tests were all 0.000. Therefore, 1,3-Propanesultone induced micronucleated reticulocytes in male CD-1 mice by double intraperitoneal treatments starting at relatively low doses.

In a Sprague Dawley peripheral blood micronucleus supporting study (equivalent or similar to OECD 474;Torous et al., 2000), groups of 5 male rats were treated by IP injection with 1,3-Propanesultone in 0.9% saline at doses of 12.5, 25 and 50 mg/kg bw/day. Animals were dosed twice (0, 24 hrs) and peripheral blood was sampled at 24 hrs after the last dose. The positive control was Ethylmethanesulphonate (100, 200 or 300 mg/kg bw/day). The frequencies of micronucleated peripheral blood reticulocytes were recorded based on the analysis of 1000 Type I and Type II (youngest immature) reticulocytes. There was a dose-dependent increase in the frequency of micronucleated reticulocytes 24 hours after dosing, compared to vehicle controls. There was a statistically significant response (p≤0.05) at all dose levels. Therefore, 1,3-Propanesultone induced micronucleated reticulocytes in male Sprague Dawley rats by double intraperitoneal treatments starting at relatively low doses.

1,3-Propenesultone is also predicted to the positive in the assay.

Justification for classification or non-classification

Based on the available information in the dossier, the substance 1,3-Propenesultone (CAS No. 21806-61-1) is classified for mutagenicity (Category 2) when the criteria outlined in Annex I of 1272/2008/EC are applied, based on the read-across data from 1,3-Propanesultone (CAS No. 1120-71-4).