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Administrative data

dermal absorption
Type of information:
other: estimated by modeling
Adequacy of study:
supporting study
Study period:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Estimations based on state of the science modelling, not measurement

Data source

Reference Type:
study report
Report date:

Materials and methods

Test guideline
no guideline followed
Principles of method if other than guideline:
estimation by modelling

Test material

Constituent 1
Reference substance name:
Details on test material:
The HYDROTOPE Category comprises the following 6 substances:
STS - Sodium toluene sulphonate (CAS 657-84-1, EC 211-522-5)
SXS - Sodium (xylenes and 4-ethylbenzene) sulphonate (EC 701-037-1)
NH4XS - Ammonium (xylenes and 4-ethylbenzene) sulphonate (EC 943-024-5)
SCS - Sodium cumene sulphonate (CAS 15763-76-5, EC 239-854-6)
KCS - Potassium cumene sulphonate (CAS 164524-02-1, EC 629-764-9)
NH4CS - Ammonium cumene sulphonate (CAS 37475-88-0, 253-519-1) 
In addition CaXS (Calcium Xylenesulphonate, CAS 28088-63-3, EC248-829-9) was evaluated for complete the assessment despite it is not registered under REACH.

Results and discussion

Any other information on results incl. tables

The modelling results show that the uptake of hydrotropes from either a diluted solution, or the concentrated product, into the stratum corneum, for short exposure durations varies between 0.36% and 0.55% of the amount applied.

- % dermal absorption is independent of concentration (i.e., the dermal flux is not saturated) and skin contact area

- % dermal absorption increases with duration exposure

- for all concentrations, the 23 hour uptake efficiency is ca 2.8% for this exposure scenario (it is unlikely if not inconceivable that anyone would be exposed to a solution containing a hydrotrope for 23 hours without removal and/or washing of the exposed surface; therefore the 2.8% uptake efficiency would represent an upper bound value)

- a 2.8% dermal absorption factor can therefore be used as an upper bound value in the exposure dose calculation

Applicant's summary and conclusion

Based on state-of-science modelling, a 2.8% dermal absorption factor can be used as an upper bound value in exposure dose calculations for hydrotropes.