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Description of key information

A theoretical toxicokinetic assessment was performed. Based on the physical/chemical properties of the substance, worst-case absorption factors for this substance are derived to be 100% (oral), 100% (inhalation) and 100% (dermal) for risk assessment purposes. The bioaccumulation potential is expected to be low.

Key value for chemical safety assessment

Bioaccumulation potential:
low bioaccumulation potential
Absorption rate - oral (%):
100
Absorption rate - dermal (%):
100
Absorption rate - inhalation (%):
100

Additional information

A theoretical toxicokinetic assessment was performed. Based on the physical/chemical properties of the substance, worst-case absorption factors for this substance are derived to be 100% (oral), 100% (inhalation) and 100% (dermal) for risk assessment purposes. The bioaccumulation potential is expected to be low.

Hydroxypropyl, 2-, trimethylammonium formate (CAS 62314-25-4) is the salt of Formic acid and (2-Hydroxypropyl)trimethylammonium. It is synthesized from trimethylamine (TMA), water, Formic acid and propylene oxide, the reaction is taking place in dipropylene glycol as solvent..

In general, a compound needs to be dissolved before it can be taken up from the gastrointestinal tract after oral administration. Hydroxypropyl, 2-, trimethylammonium formate is marketed in a propylene glycol solvent, at up to 75%. It was found to be essentially miscible in water with major components of the test item- Formic acid and the Quaternary amine cation - remaining highly solubilised after dissociation. This high water solubility means that the substance will readily dissolve into the gastrointestinal fluids, favouring passive diffusion.
        

The partition coefficients of formic acid content (approx Log Pow -2) and Quaternary Amine Cation (Log Pow <-2.00) indicate that penetration through
 lipid membranes is likely, and that therefore the ions will have the potential to reach the systemic circulation.

 Thus, as soon as it comes in contact with the fluids of the gastro-intestinal tract, a Formic Acid ion and a quaternary ammonium-ion will be formed. It is generally assumed that ionized substances do not readily diffuse across biological membranes, but the varying pH of the GI tract may have influence on the absorption of the ions. Therefore, for risk assessment purposes, a worst-case for oral absorption of Hydroxypropyl, 2-, trimethylammonium formate is used = 100%.

Once absorbed, wide distribution of the test substance throughout the body is expected based on its high water solubility and molecular weight (163.2). Formic acid will be excreted in the urine.
Metabolism of Tertiary aliphatic amines is generally well understood andis mediated primarily by cytochrome P-450 and MFAO, leading to alpha-C oxidation and N-oxidation, leading to rapid clearance (Rose & Castagnoli, 1983). However there are no definitive toxicokinetics data available for the parent substance.

Hydroxypropyl, 2-, trimethylammonium formate is marketed in a form that may be applied by spray applications, and that aerosols may be formed. Therefore, it is assumed that Hydroxypropyl, 2-, trimethylammonium formate can enter the respiratory tract. If Hydroxypropyl, 2-, trimethylammonium formate reaches the tracheobronchial region, it is likely to be dissolved within the mucus lining of the respiratory tract and to get absorbed due to its high water solubility and low molecular weight.

Furthermore, due its corrosive potential, it may damage the epithelium lining the respiratory tract, which will further promote systemic uptake of the substance. Therefore, for risk assessment purposes the inhalation absorption of Hydroxypropyl, 2-, trimethylammonium formate is set at 100%.

Hydroxypropyl, 2-, trimethylammonium formate will dissolve into the surface moisture of the skin. Uptake is facilitated by the relatively low low molecular weight
 (261.4) and high water solubility , the ions formed will influence its adsorption. The quaternary ammonium ion may bind to skin components which would limit the uptake. However, due to its corrosive properties, skin integrity will be affected leading to fast uptake of the substance. Once the skin surface is damaged, Hydroxypropyl, 2-, trimethylammonium formate will be absorbed easily due to its low molecular weight and high water solubility.

Therefore, for risk assessment purposes the dermal absorption of Hydroxypropyl, 2-, trimethylammonium formate is set at 100%.