[2-(2-methoxymethylethoxy)methylethoxy]propanol

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

GLP-studies according to OECD guideline 476 and equivalent to OECD guidelines 471, 479 and 482 are available for tripropylene glycol methyl ether. In addition, studies according to OECD guideline 473 (chromosome aberration) are available for the structural analogues propylene glycol methyl ether and diipropylene glycol methyl ether which are used for read-across.

Link to relevant study records

Reference

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1982

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: This study was conducted according to GLP and equivalent to OECD guideline 471.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

GLP compliance:

yes

Type of assay:

bacterial reverse mutation assay

Species / strain / cell type:

other: TA98, TA100, TA1535, TA1537, TA1538

Metabolic activation:

with and without

Metabolic activation system:

S9 rat liver homogenate

Test concentrations with justification for top dose:

0, 0.01, 0.1, 1, 10, or 100 mg per plate (or 0, 10, 100, 1000, 10000, or 100000 µg/plate)

Vehicle / solvent:

none (test material solutions were prepared in distilled water)
All positive controls were prepared in DMSO.

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: N-methyl-N'-nitro-N-nitrosogluanidine (TA100, TA1535/-S9); 2-nitrofluorene (TA98, TA 1538/-S9); Quinacrine mustard (TA1537/-S9) ; 2-anthramine (TA100, TA1535/+S9); 2-acetylaminofluorene (TA98, TA 1538/+S9); 8-aminoquinoline (TA1537/-S9)

Details on test system and experimental conditions:

Type: Ames test

METHOD OF APPLICATION: preincubation

DURATION
- Preincubation period: 30 min
- Incubation period: 48 hours

NUMBER OF REPLICATIONS:
3 replicates per dose

DETERMINATION OF CYTOTOXICITY
- Method: bacterial background lawn evaluation

Evaluation criteria:

Concentrations of the test chemical which are overtly toxic are easily visualized as showing no bacterial growth on the plate (i.e. absence of background lawn). Lower levels of toxicity may be seen as a thin or sparse bacterial lawn, a reduction in the number of revertants, or the appearance of microcolonies (overgrown background lawn). Positive and negative controls were run concurrently with the test chemical, and appropriate responses for these controls are prerequesites for evaluating the response of the bacteria to the test chemical.

A test chemical is considered a bacterial mutagen if both the mean number of revertant colonies observed is at least three times higher than the mean of the negative (solvent) control and at the same time it produces a dose response relationship over several concentrations. If a chemical produces reproducible reversion rates in excess of 3x over background, but no definitive dose response relationship, it is considered to be a presumptive bacterial mutagen. If a chemical produces reproducible reversion rates greater than 2x but less than 3x over the negative controls, the results are considered to be equivocal or inconclusive. Test substances failing to meet the above criteria are considered non-mutagenic in this system.

Species / strain:

S. typhimurium, other: TA98, TA100, TA1535, TA1537, TA1538

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

other: in the absence of S9 cytotoxicity was observed at 100mg/plate in all the strains and at 10mg/plate in TA 98 and TA 1538. in the presence of S9 cytotoxicity was observed at 100mg/plate in TA 98, TA 100 and TA 1535.

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Conclusions:

Interpretation of results (migrated information):
negative

Tripropylene glycol methyl ether did not cause mutations in the pre-incubation Ames plate assay with or without S-9 metabolic activation.

Executive summary:

Dowanol TPM (tripropylene glycol methyl ether) was evaluated for genetic activity in the Ames test with and without the addition of a metabolic activation preparation using a pre-incubation assay. The studies were conducted using Salmonella typhimurium strains TA98, TA100, TA1535, TA1537, TA1538.Frozen stock cultures of Salmonella typhimurium (from Bruce Ames, U California, Berkeley) were transferred to nutrient rich broth and incubated at 37C until reaching a prespecified optical density at 650 nm (108 to 109 cells/ml). This was done for each of the four tester strains (TA98, TA100, TA1535, & TA1537). To optimize contact between the bacteria and TPM, the preincubation modification was employed. This entailed 1) mixing TPM, the S-9 activation system (when appropriate), and the bacteria in a tightly capped culture tube, 2) incubating this mixture for 30 minutes at 30°C, 3) adding supplemental top agar, then 4) pouring the mixture onto plates. Plates were incubated at 37C for two days during which time histidine independent revertant colonies developed.  TPM concentrations of 0, 10, 100, 1000, 10000, or 100000 µg/plate in distilled water were tested.The activation system consisted of the 9000 x G supernatant of Aroclor 1254 induced rat liver homogenate (Litton Bionetics). Positive control substances were included in the study design to verify the sensitivity of the test organisms. Under conditions without activation, positive control substances included 1) N-methyl-N’-nitronitrosoguanidine for strains TA100 and TA1535 (10 µg/plate), 2) 2notrofluorene for strains TA98 and TA1538 (100 µg/plate), and 3) quinacrine mustard dihydrochloride for strain TA1537 (10 µg/plate). Under conditions with activation, positive control substances included 1) 2-anthramine for strains TA100 and TA1535 (10 µg/plate), 2) 2-acetylaminofluorene for strains TA98 and TA1538 (100 µg/plate), and 3) 8-aminoquinoline for strain TA1537 (25 µg/plate).
Colonies were counted with an Arteck Model 880 colony counter. Results were considered positive if the number of colonies exceeded three times background for any of the strains at any dose and if a dose response relationship was observed over several doses in any strain, with or without S-9 activation. In addition the positive response had to be reproducible in a second experiment. Results were considered negative if the revertant counts did not exceed background for any tester strain and the negative response was reproducible in a second experiment.

The validity of the assay was assessed by determining that 1) negative and positive control revertant counts fell within historical control counts and 2) toxicity did not interfere with interpretation of results.

Toxicity was elicited in all tester strains without activation at 100 mg/plate (100000 µg/plate) and at 10 mg/plate (10000 µg/plate) in strains TA98 and TA1538. With activation, toxicity occurred at the highest concentration only 100 mg/plate (100000 µg/plate) in strains TA98, TA100,& TA1535.

TPM did not cause mutations in the plate assay with or without S9 metabolic activation. A repeat experiment with the five tester strains confirmed these results.

Cytotoxis concentration:
Without activation:
100 mg/plate (100000 µg/plate) in all strains and at 10 mg/plate (10000 µg/plate) in strains TA98 and TA1538

With activation:
100 mg/plate (100000 µg/plate) in strains TA98, TA100, & TA1535

TPM was not mutagenic in any of the strains of bacteria, in either the avtivated or nonactivated assays.

 

 

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

Additional information from genetic toxicity in vitro:

All in vitro genoxicity studies conducted with tripropylene glycol methyl ether are of high quality and reliable without restrictions. The results of all studies were consistent. Tripropylene glycol methyl ether did not induce gene mutations in bacterial and mammalian cells. No increase in UDS or SCE was observed with this test material.

No chromosome aberration study in mammalian cells is available for tripropylene glycol methyl ether (TPGME). Therefore, studies on propylene glycol methyl ether (PGME) and dipropylene glycol methyl ether (DPGME) are used as surrogates for TPGME. The glycol ethers PGME, DPGME and TPGME are closely related in molecular structure and physicochemical properties and thus, the potential for toxicological effects. These are liquids with similar boiling points, moderate volatility, and high water solubility. Increasing boiling point and vapor pressure are consistent with increasing molecular weight. No differences in gene mutation potential have been observed between other glycol ethers families (e.g. mono- and di-propylene glycol n-propyl ethers and mono-, di- and tri-propylene glycol n-butyl ethers). The results obtained with propylene glycol ethers in gene mutation studies were consistently negative. Therefore, it is justified to use the gene mutation studies conducted with PGME and DPGME for read-across purposes to fill the data gap for TPGME. Negative results were obtained in the chromosome aberration studies in mammalian cells conducted with PGME and DPGME. These results are supported by the negative findings in the CHO/SCE study conducted with TPGME.

No in vivo studies are available.

Justification for selection of genetic toxicity endpoint
This study was conducted according to GLP and equivalent to OECD guideline 471

Justification for classification or non-classification

Tripropylene glycol methyl ether was not mutagenic in bacteria (Salmonella typhimuriumTA 1535, TA 1537, TA 1538, TA 98, and TA 100) and in mammalian cells, and no cytogenetic effect were observed in mammalian cells. The data available indicates that tripropylene glycol methyl ether is not genotoxic.