Resinoid of Cistus ladaniferus (Cistaceae) obtained from labdanum gum by organic solvents extraction

Melting point / freezing point

Link to relevant study record(s)

Reference

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

key study

Study period:

08-19 December 2017

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Justification for type of information:

The study was conducted according to an internationally recognised method, and under GLP. The substance is considered to be adequately characterised. Therefore full validation applies.

Qualifier:

according to guideline

Guideline:

OECD Guideline 102 (Melting point / Melting Range)

Version / remarks:

1995

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

Version / remarks:

2008

Deviations:

no

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes (incl. QA statement)

Remarks:

inspected on 15 and 16 November 2017 / signed on 15 May 2018

Type of method:

differential scanning calorimetry

Melting / freezing pt.:

< 5.1 °C

Atm. press.:

ca. 1 013 hPa

Results of the pre-test :

At room temperature, the test item was a not flowable, brown very hard and sticky paste. At 5.1°, the test item was hard and difficult to pierce. At -22.9°C and -80°C, the test item was solid like ice.

Results of the Main test using DSC method:

In all runs the mass of the crucibles was the same and the crucible was visually unchanged after the measurement.

In the cooling down phase no event could be detected during the four determinations. Therefore the DSC measurements did not show any detectable freezing.

In the heating up phase two flat and wide endothermic events were detected in the second, repetition and third determinations. The detected events cannot clearly be identified.

The first event was observed in a range of -30.61 to 3.60 °C and the second in a range of -3.02 to 54.90 °C (evaluated with the event marker function).

These events might indicate a delay of melting. As the test item is a UVCB substance it is not unusual to have flat and wide peaks and even more as one peak. But it can be some kind of transition as well.As no freezing was observed during the cooling down phase, the events in the heating up phase cannot be considered as melting without ambiguity.

 

According to the observations of the pre-test, the melting point of the test item has been stated as below 5.1°C (278.3 K) under these circumstances.

 

No observations were made which might cause doubts on the validity of the study outcome.

Conclusions:

The melting point of test substance was determined to be below 5.1°C.

Executive summary:

The melting range of the test substance was determined under GLP according to EU Method A.1 and OECD 102, using the DSC method.

A pre-test was conducted, showing that the substance was a brown not flowable very hard and sticky paste like a resin (but not solid) at room temperature. At 5.1°, the test item was hard and difficult to pierce. At -22.9°C and -80°C, the test item was solid like ice.

Four determinations were conducted including a replicate. In the cooling down phase no event could be detected, therefore the DSC measurements did not show any detectable freezing. In the heating up phase two flat and wide endothermic events were detected in the second, repetition and third determination. The first event was observed in a range of -52.00 to -19.88 °C and the second in a range of -19.98 to 17.08 °C (evaluated with the event marker function). However, considering the complex nature of the test item and as no signs of freezing were observed during the cooling down phase, these events cannot clearly be identified. These events might indicate a delay of melting or some kind of transition.

Finally, considering that in the pre-test, the test item was not frozen after a storage time of 24 hours at 5.1°C whereas it was frozen at -22.9 °C, the melting point of the test item was stated as below 5.1°C (278.3 K) under these circumstances.

Description of key information

The melting range of the test item was considered to be < 5.1°C (278.3K)

Additional information

A fully reliable GLP experimental study, conducted according to a recognized OECD/EC guidelines is available.

It is considered as a key study.