Melaleuca alternifolia, ext.

Water solubility

Administrative data

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2007

Report date:

2007

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7840 (Water Solubility)

Deviations:

no

GLP compliance:

yes

Type of method:

flask method

Remarks:

Modified flask method used - see 'details on methods' below.

Test material

Test material information

Constituent 1

Reference substance name:

Melaleuca alternifolia, ext.

EC Number:

285-377-1

EC Name:

Melaleuca alternifolia, ext.

Cas Number:

85085-48-9

Molecular formula:

Not applicable (a generic molecular formula cannot be provided for this specific UVCB substance).

IUPAC Name:

Essential oil of melaleuca alternifolia

Test material form:

liquid

Specific details on test material used for the study:

- Purity: 100%
- Lot (batch) No.: 1215
- Expiration date of the lot: 30 March 2009
- Storage condition of test material: Room temperature, protected from light.

Results and discussion

Water solubility

Water solubility:

1 420 mg/L

Conc. based on:

test mat.

Temp.:

20 °C

Remarks on result:

other: The effect of pH on the water solubility was not assessed since the test substance does not possess a dissociation constant in environmental pH ranges.

Details on results:

The detector calibration was found to be linear over the range 0 to 2010 mg/l of standard solutions in ethanol:water (50:50 v/v) with a regression coefficient of 0.9999 (see Table 1 in 'Any other information on results' below, also see attached Fig. 1).

No peaks were observed in the chromatograms of the blank solutions, indicating that the analytical method was free from interference.

The solubility values of the six principal components of the test substance were as follows:
- Alpha-terpinene: 1.7 mg/l
- p-cymene: 3.0 mg/l
- Cineole: 73 mg/l
- Gamma-terpinene: 3.0 mg/l
- Terpinen-4-ol: 1140 mg/l
- Alpha-terpineol: 87 mg/l

Any other information on results incl. tables

Table 1. Standard calibration for Tea Tree Oil by GC.

Standard concentration (mg/l)	Peak area
100.3	22.418
200.6	46.430
401.2	91.278
802.4	190.27
1204	289.86
1605	378.23
2006	480.18

Linear regression (including x = 0, y = 0): y = 0.239x - 1.69, r = 0.9999

x = concentration, y = peak area, r = regression coefficient.

Table 2 presents a summary of the results of the test and shows that the water solubility of Tea Tree Oil was 1420 ± 23 mg/l.

Table 2. Measurements of water solubility for Tea Tree Oil at 20°C.

Sample number	Time (days)	Concentration (mg/l)	Mean concentration (mg/l)	pH
1A, 1B	1	1159, 1153	1156	6.6, 6.6
2A, 2B	2	1424, 1399	1411	6.7, 6.7
3A, 3B	3	1437, 1415	1426	6.7, 6.7
4A, 4B	4	1457, 1396	1426	6.7, 6.7

Water solubility* = 1420 ± 23 mg/l

(C. of V. = 1.6%)

*Determined as mean of samples from days 2 to 4.

Applicant's summary and conclusion

Conclusions:

The water solubility of Tea Tree Oil was found to be 1420 mg/l.

Executive summary:

A GLP-compliant study was carried out to determine the water solubility of Tea Tree Oil. The study followed the requirements of EEC method A6, OECD method 105 and OPPTS method 830.7840 without significant deviation. The water solubility of Tea Tree Oil was found to be 1420 mg/l.