Registration Dossier

Physical & Chemical properties

Vapour pressure

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Administrative data

Endpoint:
vapour pressure
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
supporting study
Justification for type of information:
1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The read-across is based on the hypothesis that the Source and Target substances will have similar toxicological and ecotoxicological properties, due to their extremely close physico-chemical properties and structural similarities. For example, both the Source and Target substances are mono-constituents which share structural similarities and contain the same functional groups.
The Source substance has a comprehensive data set generated for a REACH Annex VII registration and this along with its similarity to the Target substance are considered sufficient to consider the read-across an appropriate adaptation to the standard information requirements of Annex VII of the REACH regulation for the Target substance in accordance with the provisions of Annex XI, 1.5 of the REACH regulation.
The structure the Source substance and the Target substance are structurally identical the difference lies in the salt form i.e. the counter ion. In the case of the Source substance the counter ion is a potassium ion whereas in the Target substance the counter ion is a hydrogen .

Both the Source and Target substances have similar molecular weights of 1073 and 921 respectively. The difference in molecular weight is due to the counter ions. The Source substance is the potassium salt of the Target substance.


2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)

The Source and Target substance have similar purity profiles. Water is the main impurity in both substances. Both substances contain impurities that are analogues of the Source molecule. Neither substance contains purposely added diluents or additives.
The Source and Target are manufactured using the same chemical synthetic route. The difference in salt form is the difference between the two substances.

3. ANALOGUE APPROACH JUSTIFICATION
The Target substance is the free acid salt of the Source substance, hence the Target contains all the same functional groups as the Source substance. It is anticipated that the physicochemical results of the Target and the Source substance will be very similar.
It is expected that the water solubility of the Target Substance will be slightly lower than the Source substance, although environmental conditions will impact on the degree of solubility. Even though the water solubility values are differ , both the Source and Target substance are extremely water soluble and neither will have a tendency to partition into lipids or body fats. The potential for systemic absorption is considered to be low for both substances as their bioavailability is expected to be low due to the high molecular weights of the molecules and low lipophilicity, which precludes easy passage across biological membranes.
For the full read across assessment dossier see the attached Read-across assessment framework report


4. DATA MATRIX
See Read-Across Assessment Framework Report
Cross-reference
Reason / purpose:
read-across source
Reference
Endpoint:
vapour pressure
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
the study does not need to be conducted because the melting point is above 300°C
Test material information:
Composition 1

Data source

Materials and methods

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder

Results and discussion

Applicant's summary and conclusion