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EC number: 232-221-5 | CAS number: 7790-76-3
Oral: LD50(rat, f) > 2000 mg/kg bw (OECD 420, GLP)Inhalation: LC50(rat, m/f) > 5.09 mg/L (OECD 436, GLP)Dermal: no study available
Table 1. Summary of individual bodyweights and bodyweight changes
Dose level [mg/kg bw]
Animal number and sex
Bodyweight [g] at Day
Bodyweight gain [g] during Week
* Due to a dose volume calculation error the animal received a dose of at least 2000 mg/kg. As no signs of systemic toxicity were observed, this error was considered not to have affected the outcome of the study.
Test atmosphere conditions
Temperature during exposure was considered to be satisfactory and within target range (19 - 25ºC). Relative humidity was below target range (30 - 70%). Data are presented in the following table:
Recording time (h:min from exposure start)
Relative Humidity (%)
Mean oxygen and carbon dioxide concentrations were 20.9% and 0.04% respectively. These values are considered satisfactory for inhalation studies and within target range (at least 19% and below 1% respectively). Data are presented in the following table:
Carbon dioxide (%)
The mean of the gravimetric concentrations during exposure was 5.09 mg/L air, as targeted. Data on aerosol concentrations are presented in the following table:
Group A (5.09 mg/L air). Day 1 of study
Sampling starting time (h:min from exposure start)
Sampling volume (L)
Amount of test item on the filter (mg)
Gravimetric aerosol concentration (mg/L)
Summary of mortality and clinical signs.
Animal number (sex)
Immediately post-exposure – 1 h post-exposure
1 h post-exposure
3 h exposure – Immediately post-exposure
3 h exposure – 1 h post-exposure
Summary of body weight (gain)
Body weight (gain) (g)
Acute oral toxicity
The acute oral toxicity of dicalcium pyrophosphate was tested in female Wistar rats in a study following OECD Guideline 420 and under GLP conditions. In the absence of data regarding the toxicity of the test item, one single animal was tested first at a starting dose of 300 mg/kg bw given by oral gavage. In the absence of mortality and any other signs of toxicity, a second animal was tested at a nominal oral dose of 2000 mg/kg bw (the author reported that due to an error in the dose volume calculation, the actual dose received was at least 2000 mg/kg bw). In the absence of toxic effects, a group of 4 animals were orally treated with the test material at 2000 mg/kg bw. There were no deaths and no signs of systemic toxicity were noted during the 14-day observation period. All animals showed expected gains in body weight. No abnormalities were noted at necropsy. The oral LD50 of the test material in female rats was thus determined to be > 2000 mg/kg bw.
Therefore, the test material does not fulfil the criteria for classification according to Regulation (EC) No 1272/2008 (CLP) and the Globally Harmonized System of Classification and Labelling of Chemicals (GHS), and is thus considered to be not acutely toxic by the oral route.
Acute inhalation toxicity
The acute inhalation toxicity of dicalcium pyrophosphate was evaluated in male and female Sprague Dawley rats by the acute toxic class (ATC) method according to OECD Guideline 436 and under GLP conditions. A group of three male and three female rats was exposed by nose-only, flow-past inhalation to the test material at a mean concentration of 5.09 mg/L air during 4 hours. This concentration was found to be the highest technically achievable concentration. The mean Mass Median Aerodynamic Diameter (MMAD) during exposure was 2.02 µm. More than 62% of the particles were < 4 µm, and nearly all particles (> 97%) were < 16 µm. The test material was therefore considered to be respirable to rats.
Dirty fur and chromorrhinorrhea were observed in all animals immediately after exposure. In addition, chromodacryorrhea was recorded immediately after exposure in 2 out of 3 males and in 2 out of 3 females. Dirty fur and chromorrhinorrhea were not longer observed 1 h after exposure in any of the males, but was still present in all females, with the exception of 1 out of 3 females that only presented dirty fur. Similarly, chromodacryorrhea was not longer detected in any of the males 1 h after exposure, but was still present in 1 out of 3 females. Additional clinical signs recorded on Day 1 of study were palpebral ptosis (in 1 out of 3 females) and mild piloerection (in 1 out of 3 males and 2 out of 3 females). All these clinical signs were not longer present on Day 2 of study and no other clinical signs were observed from Day 2 of study to the end of the observation period.
A slight decrease in body weight was observed in all animals from Day 1 of study to Day 2 of study. This body weight loss was transient and body weight from all animals was higher at Day 4 of study than body weight at pre-treatment, with the exception of one female whose body weight was not higher than pre-exposure bodyweight until Day 6 of study.
The LC50 of the test material in male and female rats was determined to be > 5.09 mg/L.
Therefore, the test material does not fulfil the criteria for classification according to Regulation (EC) No 1272/2008 (CLP) and the Globally Harmonized System of Classification and Labelling of Chemicals (GHS), and is thus considered to be not acutely toxic by the inhalation route.
Acute dermal toxicity
There are no studies available.
The available data indicate that the substance does not meet the classification criteria in accordance with Regulation (EC) No 1272/2008 (CLP) and the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) for acute oral and inhalation toxicity.
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