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Administrative data

basic toxicokinetics
Adequacy of study:
weight of evidence
1 (reliable without restriction)

Data source

Reference Type:
study report
Report date:

Materials and methods

Test material

Constituent 1
Chemical structure
Reference substance name:
2-phosphonobutane-1,2,4-tricarboxylic acid
EC Number:
EC Name:
2-phosphonobutane-1,2,4-tricarboxylic acid
Cas Number:
Molecular formula:
2-phosphonobutane-1,2,4-tricarboxylic acid

Results and discussion

Applicant's summary and conclusion

Executive summary:

Depending on the high water solubility and the very low logPow 2-phosphonobutane-1,2,4-tricarboxylic acid is not likely to penetrate the skin barrier. Thus, upon dermal contact, the bioavailability of Bayhibit® AM is expected to be very low and therefore negligible. Due to its very low vapour pressure, 2-phosphonobutane-1,2,4-tricarboxylic acid is assumed to be inhaled only as aerosols, and excreted by the nasal and bronchiolar mucosa due to its high water solubility. After oral uptake (preferably in the stomach), resorption and bioavailability of Bayhibit® AM are of no toxicological relevance due to the high water-solubility and low toxicity revealed in acute and subchronic oral toxicity studies. Bioaccumulation is not to be assumed because of the very low logPow. This is also supported by the low calculated BCF. As the substance is highly water-soluble, metabolising is not necessary to achieve water-soluble / excretable metabolites and therefore the formation of more reactive (toxic) products is not likely. This assumption is supported by results obtained in acute and subchronic oral toxicity studies and different in vitro tests. Based on molecular weight and water solubility, the substance is most likely excreted via the kidneys in the urine. Impurities (mainly phosphoric or phosphono carboxylic acids) are regarded as not relevant for considerations on toxicokinetics of Bayhibit® AM as their toxicological behaviour is expected to be similar to 2-phosphonobutane-1,2,4-tricarboxylic acid and is also covered by the available in vitro and in vivo studies with Bayhibit® AM.

For details please refer to the endpoint study summary on toxicokinetics, metabolism and distribution.

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