Ammonium hydrogencarbonate

Endpoint summary

Description of key information

Irritation:
- skin: 
in vitro: not irritating (OECD 431: In vitro Skin Corrosion: Human Skin Model Test with ammonium hydrogencarbonate)
in vivo: not irritating (EPA OTS 798.4470; Analogy CAS 144-55-8, sodium hydrogencarbonate)
- eyes: 
in vitro: No indication for serious eye damage (HET-CAM Test with ammonium hydrogencarbonate)
in vivo: not irritating (EPA OTS 798.4500; Analogy CAS 144-55-8, sodium hydrogencarbonate)

Key value for chemical safety assessment

Skin irritation / corrosion

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Additional information

Skin:

In vitro:

In an in vitro EpiDerm™ skin corrosion/irritation test (BASF SE, 2010), ammonium hydrogencarbonate does not show a

skin irritation potential.

In vivo:

Since no in vivo study on skin irritation testing of ammonium hydrogen carbonate was available, a study with the structural analogue sodium bicarbonate (CAS 144-55-8) was used for assessment. In this study performed according to guideline EPA OTS 798.4470 (Acute Dermal Irritation), 0.5 g sodium bicarbonate were applied to the clipped skin of six New Zealand white rabbits for four hours under semiocclusive condition (Wnorowski, 1992). The resulting effects were reversible within 48 hours and the average irritation score after 24 to 72 hours for erythema and edemas were 0.07 and 0, respectively. Thus, sodium bicarbonate was found to be not irritating to skin. Since the hydrogencarbonate ion is a dissociation product of sodium bicarbonate similar as it is after dissociation of ammonium hydrogencarbonate, the same result could be expected for ammonium hydrogencarbonate.

 

The same reason holds true for another study, where ammonium carbamate was applied on the shaved skin of two Vienna white rabbits for 1, 5 and 15 minutes under occlusive coverage (BASF, 1958). As result, neither local irritation effects nor clinical symptoms were observed in any of the treated animals. Therefore, the study was terminated 48 hours after removal of the patches. Since the ammonium ion is a dissociation product of ammonium carbamate similar as it is after dissociation of ammonium hydrogencarbonate, the same result could be expected for ammonium hydrogen carbonate.

 

Eyes:

In vitro:

In an in vitro HET-CAM test (BASF SE, 2010), ammonium hydrogencarbonate does not does not produce changes indicative for serious eye damage.

In vivo:

Since no in vivo study on irritation to eyes with ammonium hydrogencarbonate was available, a study with sodium bicarbonate (CAS 144-55-8) was available, which was performed according to guideline EPA OTS 798.4500 and where 0.1 mg of sodium bicarbonate was applied into the eyes of nine New Zealand White rabbits while the untreated eyes of the animals served as control (Wnorowski, 1992). In three of these rabbits the substance was washed out after 20 – 30 seconds after instillation. When the effects were evaluated 24 h later, the maximum total score was 2/110 with rinsing and 8.3/110 without washing while all effects were fully reversible. Thus, sodium bicarbonate was found to be not irritating to eyes. Since the hydrogencarbonate ion is a dissociation product of sodium bicarbonate similar as it is after dissociation of ammonium hydrogencarbonate, the same result could be expected for ammonium hydrogencarbonate.

Read across justification:

Ammonium bicarbonate rapidly dissociates in biological fluids to yield ammonium ion (NH₄⁺) and bicarbonate ion (HCO₃^-). Ammonium ion then reaches equilibrium with ammonia (NH₃) in a pH-dependent fashion and both are integral components of normal metabolic processes and play an essential role in the physiology of man and other species. Bicarbonate ion reaches equilibrium with CO₂and H₂O in aqueous solution and this equilibrium reaction acts as the major extracellular buffer system in blood and interstitial fluids of vertebrates.

Inorganic salts which are releasing either ammonium or bicarbonate ions are therefore in general suitable as read across substances for ammonium bicarbonate. These substances include: Sodium hydrogencarbonate, ammonium sulphate, ammonium carbamate, ammonium chloride etc.

Justification for classification or non-classification

Classification is not warranted according to the criteria of EU Directive 67/548/EEC and EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation (EC) No. 1272/2008.