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Toxicological information

Genetic toxicity: in vitro

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Administrative data

Endpoint:
in vitro gene mutation study in bacteria
Remarks:
Type of genotoxicity: gene mutation
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: comparable to guideline study with acceptable restrictions

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1989
Report Date:
1989

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
yes
Remarks:
- no strains with an AT base pair at the primary reversion site (E. coli WP2 strains or S. typhimurium TA 102) were used to detect cross-linking mutagens
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Desmodur 15 (1,5-Naphthylene diisocyanate)
- Physical state: solid
- Purity: 99.6 %
- Lot/batch No.: 113, 118, 126
- Storage condition of test material: room temperature

Method

Species / strain
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Additional strain / cell type characteristics:
not applicable
Metabolic activation:
with and without
Metabolic activation system:
S9 mix from Aroclor 1254 induced rat livers
Test concentrations with justification for top dose:
8, 40, 200, 1000, 5000 µg/plate (first trial),
50, 100, 200, 400, 800 µg/plate (second trial)
Vehicle / solvent:
Solvents used: ethylene glycol dimethylether (test substance), DMSO (positive control)
Controls
Untreated negative controls:
no
Negative solvent / vehicle controls:
yes
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: sodium azide, nitrofurantoin and 4-nitro-1,2-phenylene diamine were only used without S9 mix and 2-aminoanthracene was only used with S9 mix
Details on test system and experimental conditions:
METHOD: Standard plate test and preincubation test

Evaluation criteria:
CRITERIA FOR EVALUATING RESULTS: A reproducible and dose-related increase in mutant counts (at least twice the amount of vehicle controls) of at least one strain of bacteria is considered to be a positive result
Statistics:
not specified

Results and discussion

Test results
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
other: bacteriotoxic effects at 200 µg/plate and above
Vehicle controls validity:
valid
Untreated negative controls validity:
not examined
Positive controls validity:
valid
Additional information on results:
PRECIPITATION CONCENTRATION:
At 200 µg per plate, the substance started to precipitate.

CYTOTOXIC CONCENTRATION:
There was no indication of a bacteriotoxic effect at doses of up and including 100 µg per plate. The total bacteria counts consistently produced results comparable to the negative controls, or differed only insignificantly. Nor was any inhibition of growth noted. Higher doses had a strain-specific bacteriotoxic effect. Therefore they could only be used to a limited extent up to 1000 µg per plate.

GENOTOXIC EFFECTS:
None of the four strains concerned showed a dose-related and biologically relevant increase in mutant counts over those of the negative controls. This applied both to the tests with and without S9 mix and was confirmed by the results of the repeat tests. The positive controls sodium azide, nitrofurantoin, 4-nitro-1,2-phenylene diamine and 2-aminoanthracene increased mutant counts to well over those of the vehicle controls, and thus demonstrated the system's sensitivity and the activity of the S9 mix.
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

Table 1: Summary of results from the Salmonella mutagenicity assay (first trial) with 1,5-NDI (mean values of revertants per plate)

 Dose (µg per plate)

Without metabolic activation

   TA 98  TA 100  TA 1535  TA 1537

 Solvent EGDE

21 92 13 6
 8 25 96 13 8
 40 28 108 10 8
 200 16 45 11 3
1000 --- --- --- ---
5000 --- --- ---  ---
 Positive control 163 489 1012 83
 Dose ( µg per plate )

With metabolic activation (liver S9 mix)

   TA 98  TA 100  TA 1535  TA 1537
 Solvent EGDE 41 142 15  12
8 42 146  16 14
 40 45 163  13 15 
 200 39 220 15 16
 1000 --- 172 ---  ---
 5000 --- ---  --- ---
 Positive control 581 903  263 89

Table 2: Summary of results from the Salmonella mutagenicity assay (second trial) with 1,5-NDI (mean values of revertants per plate)

 Dose (µg per plate)

Without metabolic activation

   TA 98  TA 100  TA 1535  TA 1537

 Solvent EGDE

26 60 8 10
50 20 69 6 7
100 20 68 7 6
200 11 36 4 3
400 --- 0 --- 0
800 --- --- 0  ---
 Positive control 87 320 679 60
 Dose ( µg per plate )

With metabolic activation (liver S9 mix)

   TA 98  TA 100  TA 1535  TA 1537
 Solvent EGDE 40 121 13  16
50 44 160  16 18
100 47 137  13 17 
200 49 166 13 17
400 40 96 13  10
800 --- 97 --- ---
 Positive control 660 936  297 88

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative
Executive summary:

In an Ames test with the S. typhimurium strains TA 98, TA 100, TA 1535, and TA 1537 1,5-naphthylene diisocyanate revealed no mutagenic activity in the absence and in the presence of a metabolic activation system (OECD TG 471).