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Administrative data

Description of key information

Based on key study results, the oral LD50 of melamine cyanurate in rats is >2000 mg/kg bw (Bromine Compound Ltd, 2000) and the inhalation LC50 (4 hours) in rats is >5.1 mg/L (BASF SE, 2016).

In view of the overall information, the dermal LD50 in rats is considered to be >2000 mg/kg bw.

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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Guideline study (Acute Toxic Class Method; GLP, QUA)
Qualifier:
according to
Guideline:
OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)
Qualifier:
according to
Guideline:
EU Method B.1 tris (Acute Oral Toxicity - Acute Toxic Class Method)
Qualifier:
according to
Guideline:
other: US FDA Title 21 Code of Federal Regulations Part 58; US EPA (FIFRA), Title 40 Code of Federal Regulations Part 160; US EPA (TSCA), Title 40 Code of Federal Regulations Part 792;
Qualifier:
according to
Guideline:
other: Japanese Ministry of Agriculture, Forestry and Fisheries, 59 NohSan, Notifications No.3850; Japanese Ministry of International Trade and Industry, Kanpogyo No.39 Environmental Agency, Kikyoku No.85; Japanese Ministry of Health and Welfare, Ordinance No.21
GLP compliance:
yes (incl. certificate)
Remarks:
OECD Principles of Good Laboratory Practice
Test type:
acute toxic class method
Limit test:
yes
Specific details on test material used for the study:
- Name of test material (as cited in study report): FR-6120
- Physical state: white powder
- Analytical purity: ca. 99.5%
- Impurities (identity and concentrations): water (0.27%), Melamine (0.19%) and cyanuric acid (0.012%) (weight%)
- Purity test date: 04 May 2000
- Lot/batch No.: 37432-18-3
- Expiration date of the lot/batch: 22 May 2001
- Stability under test conditions: not indicated
- Storage condition of test material: at room temperature in the dark
Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Rat, Wistar strain Crl:(WI) BR (outbred, SPF-Quality) from Charles River Deutschland, Sulzfeld, Germany.
- Age at study initiation: Young adult animals (approx. 7 weeks old) were selected
- Weight at study initiation: weight variation did not exceed +/- 20% of the sex mean (see Table 1)
- Fasting period before study: food was withheld overnight (for a maximum of 20 hours) prior to dosing until approximately 3-4 hours after administration of the test substance.
- Housing: Group housing of 3 animals per sex per cage in labelled polycarbonate cages containing purified sawdust as bedding material (SAWI, Jelu Werk, Rosenberg, Germany).
- Diet (e.g. ad libitum): Free access to standard pelleted laboratory animal diet (from Carfil Quality BVBA, Oud-Turnhout, Belgium).
- Water (e.g. ad libitum): free access to tap-water.
- Acclimation period: at least 5 days before start of treatment under laboratory conditions

ENVIRONMENTAL CONDITIONS
A controlled environment was maintained in the room with optimal conditions
- Temperature (°C): 21°C
- Humidity (%): 50%
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12 hours artificial fluorescent light and 12 hours dark per day
Route of administration:
oral: gavage
Vehicle:
other: water (Milli-U)
Details on oral exposure:
VEHICLE
- Concentration in vehicle: 200 mg/ml
- Amount of vehicle (if gavage): 10 ml/kg
- Justification for choice of vehicle: the vehicle was selected based on a pretest performed at the testing facility

MAXIMUM DOSE VOLUME APPLIED: 10 ml/kg

CLASS METHOD (if applicable)
- Rationale for the selection of the starting dose: the toxicity of the test substance was assessed by stepwise treatment of groups of 3 animals. The first group was treated at a dose level of 2000 mg/kg body weight. The absence or presence of mortality of animals dosed at one step determined the next step, based on the test procedure defined in the guidelines. The onset, duration and severity of the signs of toxicity were to be taken into account for determination of the time interval between the dose groups.
Doses:
2000 mg/kg bw
No. of animals per sex per dose:
3 (the male animals were first tested, followed by female animals, in the absence of mortality in male, one day later)
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: mortality/viability (twice daily); body weights (days 1; pre-administration, 8 and 15); clinical signs [at periodic intervals on the day of dosing and once daily thereafter, until day 15. The symptoms were graded according to fixed scales and the time of onset, degree and duration were recorded.
- Necropsy of survivors performed: yes; at the end of the observation period, all animals were sacrificed by asphyxiation using an oxygen/carbon dioxide procedure and subjected to necropsy. Descriptions of all internal macroscopic abnormalities were recorded.
- Other examinations performed: clinical signs, body weight
Statistics:
none necessary
Preliminary study:
not applicable
Sex:
male/female
Dose descriptor:
LD50
Effect level:
> 2 000 mg/kg bw
Remarks on result:
other: No female (0/3) or male (0/3) animal died at this unique dose level
Mortality:
No mortality occurred.
Clinical signs:
No clinical signs were noted.
Body weight:
The body weight gain shown by the animals over the study period was considered to be similar to that expected of normal untreated animals of the same age and strain (Table 1).
Gross pathology:
Macroscopic post mortem examination of the females revealed thickening of the glandular mucosa of the stomach. No abnormalities were found in males.
Other findings:
none reported

Table 1: Body weight (all means of 3 animals)

Group / Sex

Mean body weights ± standard deviation (g) at indicated time period

Day 1

Day 8

Day 15

Group 1 / Males

251 ± 9

320 ± 17

362 ± 31

Group 2 / Females

185 ± 6

224 ± 15

239 ± 12

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
discriminating dose
2 000 mg/kg bw
Quality of whole database:
Valid without restriction

Acute toxicity: via inhalation route

Link to relevant study records
Reference
Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2016
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: OECD guideline and GLP-compliant study
Qualifier:
according to
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Test type:
acute toxic class method
Limit test:
yes
Specific details on test material used for the study:
Batch no. 52334524U0
Homogeneity: given visual
Storage stability: Expiry date: 15 Sep 2020
Melapur MC25
Identifier: CAS 37640-57-6

Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Laboratories, Research Models and Services, Germany GmbH,
- Age at study initiation: about 8 – 12 weeks old
- Weight at study initiation: animals of comparable weight (+/- 20% of the mean body weight)
- Fasting period before study: no
- Housing: single houing or up to 5 animals
- Diet: Kliba laboratory diet, ad libitum
- Water: tap water, ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature: 20–24 °C
- Humidity: 30-70 %
- Air changes: 15 changes per hour
- Photoperiod: 12 hours light / 12 hours dark
Route of administration:
inhalation: dust
Type of inhalation exposure:
nose only
Vehicle:
air
Mass median aerodynamic diameter (MMAD):
>= 3.3 - <= 3.5 µm
Geometric standard deviation (GSD):
>= 2.1 - <= 2.6
Remark on MMAD/GSD:
Two samples were analyzed.
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: For each test group the dusts were produced inside the inhalation system with a dust generator and compressed air and passed into the inhalation system. The concentrations were adjusted by varying the apertural width rotation of the dosing wheel of the dust generator.
- Exposure chamber volume: 34 L
- Method of holding animals in test chamber: restraining tubes
- Source and rate of air: central air conditioning system, 0.8 m³/h
- Method of conditioning air: Central air conditioning system provided cold air of about 15°C. This cold air passed through an activated charcoal filter, adjusted to room temperature of 20 to 24°C and passed through a second particle filter (H13 (HEPA) Camfil Farr, Germany). The so generated conditioned air was used to generate inhalation atmospheres.
- System of generating particulates/aerosols: The test item was stirred in its container before a sample for dust generation was taken. The test item was desagglomerated in a mixer (mixing for 10 seconds) before introduction into the dust generator via the dosing wheel (Gericke/BASF).
- Method of particle size determination: Stack Sampler Mark III (Andersen). Before sampling, impactor stages were assembled with preweighed glass fiber collecting discs, and equipped with a backup particle filter. The impactor was connected to a vacuum pump, and for each test group samples were taken from the breathing zone of the animals. Sampling occurred 30 minutes (or later) after the beginning of the exposure.
- Treatment of exhaust air: The exhaust air was filtered and conducted into the exhaust air of the building.

TEST ATMOSPHERE
- Brief description of analytical method used: gravimetric, filtration equipment with probe, internal diameter: 7 mm
- Samples taken from breathing zone: yes

VEHICLE
In technical trial runs, various modifications of the dust generation procedure were tested to produce the limit concentration of 5 mg/L. To improve the flowability, 1% AEROSIL® R 972 was added to the test item. AEROSIL® is a brand name of various amorphous silicas produced by Evonik Industries, Frankfurt am Main, Germany. AEROSIL® R 972 is a hydrophobic fused silica, which is used to improve free flow and anti-caking characteristics of powders.

TEST ATMOSPHERE:
- Particle size distribution: Based on cascade impactor measurements. The calculation of particle size distribution was carried out by means of mathematical methods for evaluating particle measurements.
Analytical verification of test atmosphere concentrations:
yes
Duration of exposure:
4 h
Concentrations:
5 mg/L
The actual measured concentration was 5.057 mg/L
No. of animals per sex per dose:
5 rats
Control animals:
yes
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Individual body weight was determined once during the acclimatization period, at the start of the exposure period (Day 0) and at least on Days 1, 3 and 7, and weekly thereafter, or before the sacrifice of the animals at the end of the observation period.
- Clinical observations were recorded for each animal before exposure, separately several times during exposure (usually hourly) and after exposure. At least once daily on the preexposure day and during the post exposure observation period.
- Necropsy of survivors performed: yes
Statistics:
LC50 values were calculated for males, females and both sexes combined using a binomial test.
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 5.1 mg/L air (analytical)
Based on:
test mat.
Exp. duration:
4 h
Remarks on result:
other: No mortality was observed.
Mortality:
No lethality was observed in male and female animals during the study period of 14 days.
Clinical signs:
Laboured respiration was noted during the exposure period (Hour 2 to Hour 4) and fur contaminated with test item was noted on Day 0. No abnormalities were detected in the animals during the post exposure observation period from Day 1 onwards.
Body weight:
The mean body weights of the animals decreased on the first post exposure observation days but increased thereafter.
Gross pathology:
There were no test item-related macroscopic findings at scheduled necropsy.

Analytical measurements

Exposure conditions: Supply air: 1.5 ± 0.0 m³/h, exhaust air: 0.6 ± 0.0 m³/h,

Test substance preparation: 62.8 g/h, temperature: 22.8 ± 0.3 °C, relative humidity: 22.2 ± 1.3 %

Analytical concentration: 5.075 ± 0.622 mg/L (nominal concentration: 52.3 mg/L)

Particle size analysis: MMAD (µm) / GSD: 3.5 / 2.6 (sample 1), 3.3 / 2.1 (sample 2)

 

Interpretation of results:
GHS criteria not met
Executive summary:

In a GLP-compliant acute inhalation toxicity study according to OECD 403 (single 4 -hour exposure, nose only; limit test), male and female Wistar rats were exposed to the test item melamincyanurat as a dust (key study, BASF 13I0834/09I058). Mortality, clinical signs and body weights were recorded during the 14 day observation period. At necropsy, a macroscopical examination was conducted. The actual measured test item concentration was 5.057 mg/L. Particle size distributions were well within the respirable range, with mass median aerodynamic diameters (MMADs) of 3.5 and 3.3 μm and geometrical standard deviations of 2.6 and 2.1. There was no mortality. Clinical signs of toxicity comprised of laboured respiration noted during exposure (Hour 2 to Hour 4) and substance contaminated fur (Day 0). No clinical signs were observed from study Day 1 onwards. Mean body weights decreased on the first post exposure observation days but increased thereafter. No gross pathological abnormalities were detected. The 4 -hour LC50 value was deemed as > 5.1 mg/L (calculated based on analytical concentraton) under the conditions of this study.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
discriminating conc.
5 100 mg/m³
Quality of whole database:
Valid without restriction

Acute toxicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
discriminating dose
2 000 mg/kg bw
Quality of whole database:
The key study is the in-vitro skin permeability study in the toxicokinetic section.

Additional information

Reliable data is available regarding acute oral toxicity in rats (Bromine Compounds Ltd 2000a). The study was performed following OECD testing guideline 423 and GLP. The acute oral toxicity in mice (Wendtland 1980) deviates in reporting details and investigated parameters from the OECD testing guidelines. For example, the post-observation period was only 7 days and gross pathology was not performed. As the tested dose of 12000 mg/kg bw is very high, this study contributes to the hazard assessment. Both studies were performed with gavage application. In rats, no mortality was observed in male and female animals at a single dose of 2000 mg/kg bw. In mice, a single dose of 12000 mg/kg bw caused mortality of 4/10 female and 1/10 male animals during an observation period of 7 days. Acute oral LD50 values of 3461±155 and 4140±438 mg/kg bw were reported in publications in russian language (Aleksandryan 1984a and Babayan 1985), no experimental details were given and therefore it is not possible to evaluate that information.

A reliable acute inhalation toxicity study in rats (BASF SE, 2016), demonstrated a low toxicity of melamine cyanurate via the inhalation route. The LC50 for a 4 hour exposure to a respirable dust aerosol of melamine cyanurate was determined to be >5.1 mg/L (males, females, sexes combined).

The acute oral toxicity data was published together with acute intraperitoneal, dermal and inhalation data as well as a 4-month inhalation study with (Babayan 1985 and 1986, Aleksandryan 1984 and 1986) The information on design and results is spread over the publications and it is so limited that no validity assessment is possible. However, the set of publications describe details on toxic effects on kidneys including changes in blood urea nitrogen content and plasma creatinine levels that are consistent with reliable data on repeated dose toxicty.

For the supplementary acute inhalation study, rats were presumably exposed to dust at concentrations of 170, 241, 594 and 2238 mg/m3 air. Only 241 and 2238 mg/m3 are mentioned in the 1984 publication; the later publication (Aleksandryan 1986) also mentions 170 and 594 mg/m3 air. It seems as if the whole animal was exposed because the size of the chamber is given. For some parameters, it is difficult to determine whether they belong to the investigation with rats or with mice. The concentration of 241 mg/m3 air is reported as being the threshold concentration for the increase in urea and nitrogen in blood of rats.

For mice, the same publications report an LC50 after 2h exposure of 1237 mg/m3 air.

For acute dermal toxicity, the LD50 is reported as 5525 ± 158 mg/kg bw for rats without further information such as duration of exposure or observation period (Babayan 1985). During the skin sensitization study (Bromine Compound Ltd. 2000d), guinea pigs were treated with intradermal injection of ca 20 mg/kg bw plus an epicutaneous dose of ca 200 mg/kg bw applied in olive oil for 24h. No clinical signs of toxicity and no mortality was observed during the 14 -day induction phase.

The acute intraperitoneal LD50 was reported as 2020 ± 437 mg/kg bw for rats and 1125 ± 207 mg/kg bw for mice (Babayan 1985).

Considering the results of the reliable key acute inhalation toxicity study, the acute toxicity of melamine cyanurate via the inhalation route is above the limit concentration of 5 mg/L.

Considering the overall information, the acute dermal toxicity of melamine cyanurate in rats is considered to be above the limit dose of 2000 mg/kg bw.


Justification for classification or non-classification

Dangerous Substance Directive (67/548/EEC)

The available studies are considered reliable and suitable for classification purposes under 67/548/EEC. As a result the substance is not considered to be classified for acute oral, inhalation and dermal toxicity under Directive 67/548/EEC, as amended for the 28th time in Directive 2001/59/EC.

Classification, Labelling, and Packaging Regulation (EC) No. 1272/2008

The available experimental test data are reliable and suitable for classification purposes under Regulation 1272/2008. As a result the substance is not considered to be classified for acute oral, inhalation and dermal toxicity under Regulation (EC) No. 1272/2008.