2-tert-butylaminoethyl methacrylate

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vivo

Description of key information

The available studies for genotoxicity with 2-tert-butylaminoethyl methacrylate are an Ames bacterial gene mutation assay in S. typhimurium strains TA1535, TA1537, TA98 and TA100 to OECD guideline 471.  Also Escherichia Coli, reverse mutation assay in Ecoli WP2 uvr A and WP2 uvr A pKM 101.  Also an in-vitro mammalian chromosomal aberration test in cultured human lymphocytes.

In addition there are two studies available for the read across substance 2-dimethylaminoethyl methacrylate, there is HPRT gene mutation assay in V79 Chinese hamster cells and an in-vivo mouse micronucleus assay for clastogenicity.

Link to relevant study records

Reference

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

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

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Review by Japanese government and included in the SIDS dossier for 2-dimethylaminoethyl methacrylate as Klimisch 1.

Qualifier:

according to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

GLP compliance:

yes

Type of assay:

micronucleus assay

Species:

mouse

Strain:

NMRI

Sex:

male/female

Details on test animals or test system and environmental conditions:

Summary does not include these details

Route of administration:

oral: gavage

Vehicle:

Negative control, distilled water
Positive control: Cyclophosphamide , physiological saline (0.9% NaCl)

Details on exposure:

Single oral (gavage) dose followed by sampling at 24hour, 48hour and 72 hours after dosing.

Duration of treatment / exposure:

Single oral (gavage) dose followed by sampling at 24hour, 48hour and 72 hours after dosing.

Frequency of treatment:

Single dose

Post exposure period:

Up to 72 hours

Remarks:

Doses / Concentrations:
1000 mg/kg limit dose
Basis:
nominal in water

No. of animals per sex per dose:

5

Control animals:

yes, concurrent vehicle

Positive control(s):

Cyclophosphamide, dose 40mg/kg bodyweight

Tissues and cell types examined:

Polychromatic erythrocytes from the bone marrow in the femur.

Details of tissue and slide preparation:

Summary does not include these details

Evaluation criteria:

Cytotoxicty was assess by comparing the ratio of the PCE (polychromatic erythrocytes) the NCE (normochromatic erthrocytes follwing and staining. A decrease in the PCE/NCE ratio compared to the negative controls would be taken to indicate cytotoxicty and confirm that the test substnace or a metaboite have reached the bone marrow.

Statistics:

Summary does not include these details

Sex:

male/female

Genotoxicity:

negative

Toxicity:

no effects

Vehicle controls validity:

valid

Negative controls validity:

not applicable

Positive controls validity:

valid

Sampling time: 24 hours

Group	Dose mg/kg Bwt	PCE with Micronuclei	Micronuclei in 1000 PCE	PCE/NCE (mean)
Solvent control	0	0.06	0 - 2	1000/554
2 -dimethylaminoethyl methacrylate	1000	0.03	0 - 2	1000/653
Cyclophosphamide	40	0.75	1 - 13	1000/742

Sampling Time: 48 hours

Group	Dose mg/kg bw	PCE with Micronuclei	Micronuclei in 1000 PCE	PCE/NCE (mean)
Solvent control	0	0.04	0 - 2	1000/680
2 -dimethylaminoethyl methacrylate	1000	0.04	0 - 1	1000/744

Sampling time: 72 hours

Group	Dose mg/kg bw	PCE with Micronuclei	Micronuclei in 1000 PCE	PCE/NCE (mean)
Solvent control	0	0.06	0 - 4	1000/594
2 -dimethylaminoethyl methacrylate	1000	0.09	0 - 2	1000/506

Conclusions:

Interpretation of results (migrated information): negative
2-dimethylaminoethyl methacrylate was not clastogenic in vivo in the mouse micronucleus test at a 1000 mg/kg limit dose which produced toxic effect in the mice in a preliminary study. There was no indication of cytotoxicity in the bone marrow.

Executive summary:

Type : Micronucleus assay

Species : mouse

Sex : male/female

Strain : NMRI

Route of admin. : gavage

Exposure period : one dose

Doses : 1000 mg/kg (maximum tolerated dose)

Result : negative

Method : OECD Guideline 474 "Genetic Toxicology: Micronucleus Test"

Year : 1989

GLP : yes

Test substance : as prescribed by 1.1 - 1.4

Remark : In comparison with the corresponding negative controls there was no

substantial enhancement in the frequency of the detected micronuclei at

any preparation interval after application of the test article. The mean values

of micronuclei observed after treatment with MADAME were in the same

range compared to the negative control groups. In the positive control group

a distinct increase of induced micronuclei frequency was observed.In

conclusion, the test article did not induce micronuclei as determined by the

micronucleus test in the bone marrow cells of the mouse.

Source : Roehm,

EUROPEAN COMMISSION - European Chemicals Bureau Ispra (VA)

Test condition : Group: 5 males and 5 females

Negative control: distilled water

Positive control: Cyclophosphamid in physiological serum (NaCl)

Dose: 40 mg/kg

Bone marrow preparation: 24, 48 and 72 hrs after application.

Analysis : 1000 PCE (Polychromatic Erythrocytes) per animal

By a preliminary test, 1000 mg/kg b.w. was estimated to be the maximum

tolerated dose. The animals expressed toxic reactions. After treatment with

the test article the ratio between PCEs and NCEs was not affected as

compared to the corresponding negative controls, thus indicating no

cytoyoxic effects.

Conclusion

2-dimethylaminoethyl methacrylate was not clastogenic in vivo in the mouse micronucleus test at a 1000 mg/kg limit dose.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

Additional information from genetic toxicity in vivo:

The effects seen in the TA1535 and TA 100 strains were small but greater than the control range, however they were not reproducible and did not show a dose response. Therefore these differences were considered not to have been treatment related and overall 2-tert-butylaminoethyl methacrylate was considered not to have mutagenic activity.

The other study available on 2-tert-butylaminoethyl methacrylate is an in-vitro mammalian chromosomal aberration test in cultured human lymphocytes which is Klimisch 1 to OECD guideline 473. In this study the 2-tert-butylaminoethyl methacrylate induced chromosome abberations with and without metabolic activation. This was only seen at the 20 hour harvest, similar effects were not seen with 3 hour and 44 hour harvests. It was concluded that 2-tert-butylaminoethyl methacrylates was clastogenic in-vitro in cultured human lymphocytes. The read across substance 2-dimethylaminomethacrylate was also reported to be clastogenic in vitro in cultured human lymphocytes (2002 SIDS dossier 2-dimethylaminoethyl methacrylate CAS No 2867-47-7).

We do not have a mammalian cell gene mutation assay for 2-tert-butylaminoethyl methacrylate. However we do have for the read across substance 2-dimethylaminoethyl methacrylate, an HPRT gene mutation assay in V79 Chinese hamster cells carried out to OECD guideline 476, which is Klimisch 1 and fully GLP compliant. This study showed no indication of mutagenicity even at cytotoxic concentrations both with and without S-9 metabolic activation.

There is also an in-vivo mouse micronucleus assay for the read across substance 2-dimethylaminoethyl methacrylate. This study was Klimisch 1 to OECD guideline 474 and used a maximum tolerated dose of 1000 mg/kg which was established in a preliminary study. This study showed the expected responses with the positive and negative controls and showed no indication of any increase in the incidence of micronuclei in the polychromatic erythrocytes. It was conclude that 2-dimethylaminoethyl methacrylate was not clastogenic in vivo. This indicates that the clastogenicity seen in vitro is not confirmed in vivo. No methacrylates are classified as genotoxic, several show indications in vitro of clastogenicity at high concentrations that are cytotoxic, but all those tested are negative in vivo.

Taking all the available information it is concluded that 2-tert-butylaminoethy methacrylate is not genotoxic in vivo. Based on the available data it does meet the criteriafor classification for mutagenicity by the EU CLP(GHS)criteria.

Justification for selection of genetic toxicity endpoint

This study is an in-vivo test with the read across substance 2-dimethylaminoethyl methacrylate, there were toxic effect s reported in the mice in a preliminary study, therefore this study had a maximum dose at 1000mg/kg bodyweight.  This study showed that the clastogenicity seen in the in-vitro human lymphocyte test was not confirmed in-vivo.

Justification for classification or non-classification

Taking all the available information it is concluded that 2-tert-butylaminoethyl methacrylate is not genotoxic in vivo. Based on the available data it does meet the criteria for classification for mutagenicity by the EU CLP(GHS)criteria.