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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Endpoint:
basic toxicokinetics
Type of information:
other: assessment based on information available
Adequacy of study:
key study
Study period:
July 2012
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Non-GLP assessment report.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2012

Materials and methods

Objective of study:
other: toxicokinetic assessment
Test guideline
Qualifier:
no guideline required
Principles of method if other than guideline:
An expert assessment was made based on all data available.
GLP compliance:
no

Test material

Constituent 1
Reference substance name:
B508
IUPAC Name:
B508
Details on test material:
- Name of test material (as cited in study report: B508
- Physical state: powder
- Analytical purity: 100%

Test animals

Species:
other: none

Administration / exposure

Route of administration:
other: oral, dermal and inhalation
Vehicle:
other: not applicable
Details on study design:
A toxicokinetic assessment has been performed based on available physico-chemical properties and toxicological data of the substance.

Results and discussion

Main ADME results
Type:
absorption
Results:
For risk assessment purposes, oral absorption is set at 50%, inhalation absorption is set at 100% and dermal absorption is set at 10%.

Any other information on results incl. tables

As no partition coefficient could be determined, this parameter cannot be used in the prediction of toxicokinetics of B508.

Generally, a solid has to be dissolved before it can be absorbed. The relatively high molecular weight (>500 g/mol) and the low water solubility (<0.967 mg/L) of B508 predict absorption in the gastro-intestinal tract by passive diffusion to be unlikely. In the 28-day study urine was not discoloured due to the test substance, but faeces were. Therefore, for risk assessment purposes, the oral absorption of B508 is set at 50% (1). The results of the toxicity studies do not provide reason to deviate from this proposed oral absorption percentage.

 

Based on the relatively high molecular weight and low water solubility B508 is expected to have a limited distribution once absorbed. Accumulation in the lungs may occur as was demonstrated in the acute inhalation study by blue foci in the lungs. As no partition coefficient could be determined no further prediction of bioaccumulation can be made. Absorbed B508 may be metabolised and/or conjugated (2). The conjugates are expected to be excreted via the faeces as they are relatively high molecular weight compounds.

 

The low vapour pressure (<8.40´10-7Pa) indicates that B508 is not available for inhalation as a vapour. At least 50% of particles is small enough to be inhaled and more than 10% is expected to reach the alveolar region of the respiratory tract. The low water solubility (<0.967 mg/L) enhances penetration to the lower parts of the respiratory tract where B508 might be taken up by micellular solubilisation. For risk assessment purposes the inhalation absorption of B508 is set at 100%. The result of the acute inhalation study does not provide reason to deviate from this proposed inhalation absorption percentage.

 

A solid has to dissolve into the surface moisture of the skin before uptake can occur. The high molecular weight and the low water solubility indicate a low expected dermal absorption of B508. According to the criteria given in the REACh guidance (1): 10% dermal absorption will be considered in case MW >500 and log Pow <-1 and >4, otherwise 100% dermal absorption should be used. Therefore, for risk assessment purposes, 10% dermal absorption of B508 is proposed.

 

Based on the present data, no additional conclusions can be drawn on the distribution, metabolism and excretion of B508 after dermal and inhalatory absorption.

1.    Guidance for the implementation of REACH. Guidance on information requirements and chemical safety assessment. Chapter R.7c: Endpoint specific guidance. European Chemical Agency, May 2008.

2.    A. Parkinson. In: Casarett and Doull’s Toxicology, The basic science of poisons. Sixth edition. Ed. C.D. Klaassen. Chapter 6: Biotransformation of xenobiotics.,, 2001.

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information): bioaccumulation potential cannot be judged based on study results
For risk assessment purposes, oral absorption is set at 50%, inhalation absorption is set at 100% and dermal absorption is set at 10%.