Propionaldehyde

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (LLNA)

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:

2004

Report date:

2004

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 429 (Skin Sensitisation: Local Lymph Node Assay)

Deviations:

yes

Remarks:

no DPM determined

GLP compliance:

yes (incl. QA statement)

Remarks:

BASF AG Experimentelle Toxikologie und Okologie

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

Propionaldehyde

EC Number:

204-623-0

EC Name:

Propionaldehyde

Cas Number:

123-38-6

Molecular formula:

C3H6O

IUPAC Name:

propanal

Specific details on test material used for the study:

- Name of test material (as cited in study report): propionaldehyde
- Analytical purity: 99.6%
- Physical state: liquid / colorless, clear
- Lot/batch No.: 04449775L0
- Stability under test conditions: the stability under storage conditions was confirmed by reanalysis
- Storage condition of test material: refrigerator, exclusion of air (covered with N2)

In vivo test system

Test animals

Species:

mouse

Strain:

other: CBA/CaOlaHsd

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Winkelmann GmbH, Borchen, FRG
- Age at study initiation: about 9 weeks old
- Weight at study initiation: body weight between 16.8 and 20.3 g at the beginning of the study
- Housing: the single housed animals were identified by cage cards
- Diet: Kliba-Labordiät, Provimi Kliba SA, Kaiseraugust, Basel, Switzerland, ad libitum
- Water: tap water; ad libitum
- Acclimation period: 29 days before the first test substance application

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-24
- Humidity (%): 30-70
- Photoperiod (hrs dark / hrs light): 12/12

Study design: in vivo (LLNA)

Vehicle:

other: acetone was used as the vehicle because good solubility of the preparation was achieved

Concentration:

1%, 3% and 10% w/w of the test substance in acetone or with the vehicle alone (correctness tested concentrations confirmed by analysis)

No. of animals per dose:

6

Details on study design:

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
Groups /Number of animals /Animal number /Induction (3 percutaneous applications at day 0, 1 and 2)
Control group 1 /6 /49-54 /Vehicle: acetone
Test group 2 /6 /25-30 /Test substance 1 % in acetone
Test group 2 /6 /31-36 /Test substance 3% in acetone
Test group 2 /6 /37-42 /Test substance 10% in acetone

- Name of test method: the LLNA was performed based on the method of Kimber, I. and Basketter, D.A. (1992).
- Criteria used to consider a positive response: the study procedure was modified according to the method described by Ulrich, P., Streich, J. and Suter, W. (2001), who suggest to evaluate the skin sensitizing potential of test substances by determination of lymph node response using Iymph node weight and lymph node cell count as parameters which are set into perspective to ear weight as an indicator of skin irritation.

TREATMENT PREPARATION AND ADMINISTRATION:
The test substance preparations were produced on a weight by weight (wlw) basis shortly before the application by stirring with a magnetic stirrer and applied as a solution for all applications. The correctness of the concentration of the test substance preparations was investigated. Percutaneous application on dorsal part of both ears (each 25 µl per ear of test substance preparation or vehicle alone).

Positive control substance(s):

other: positive control not included into this study. Historical studies with alpha-Hexylcinnamaldehyde, (85%) are performed twice a year in the laboratory showing that the test system is able to detect sensitizing compounds under the test conditions chosen

Statistics:

Mean values and standard deviations of the measured parameters were calculated for the test and control groups from the individual values. The indices of lymph node weight, cell count and ear weight were calculated as the ratio of the test group mean values for these parameters divided by those of the vehicle control group. Lymph node weight, cell count and ear weight were evaluated with a WILCOXON – Test.

Results and discussion

Positive control results:

The results of the most recent study is included in the study report

In vivo (LLNA)

Results

Results 1

Parameter:

SI

Remarks on result:

other: see Remark

Remarks:

see table 1 and 2. - Lymph node weights and cell counts: treatment of the mice with the 10% test substance preparation induced small but statistically significant increase in lymph node cell counts as compared to the vehicle control group. The lymph node weights were statistically increased and therefore in line with the cell counts. No statistical increase was caused by treatment with 1 % and 3% test substance preparations in both parameters. - Ear weights: treatment of the mice with 1 %, 3% and 10% test substance preparations induced statistically significant increase in ear weight as compared to the vehicle control group.

Results 2

Parameter:

other: disintegrations per minute (DPM)

Remarks on result:

other: not determined

Any other information on results incl. tables

Table 1: Lymph node weight and cell count

Test group	Treatment (% test substance in vehicle)	Lymph node weight (mg)		Cell count [counts/lymph node pair]
		Mean ± SD	Index	Mean ± SD	Index
1	Vehicle	5.0±0.4	1.00	9350000±790470	1.00
2	1%	4.8±0.9	0.94	8587500±1867302	0.92
3	3%	4.7±0.7	0.94	8848667±1411236	0.95
4	10%	6.0±0.8	1.19	10841667±1974725	1.16

  

Table 1: Ear weight

Test group	Treatment (% test substance in vehicle)	Ear weight (mg)
		Mean ± SD	Index
1	Vehicle	26.0±0.6	1.00
2	1%	30.5±1.5	1.17
3	3%	28.9±1.4	1.11
4	10%	30.0±1.0	1.15

 

- Body weights: the expected body weight gain was generally observed in the course of the study.

- Other findings: no abnormalities were observed during general observation. No signs of systemic toxicity were noticed.

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Conclusions:

- The test substance induced a small, statistically significant, but not biologically relevant response of the auricular lymph fades when applied as 10% preparation in acetone but not when applied as 3% or 1 % concentrations.
- The ear weights indicated some irritation of the ear skin when applied as 1%, 3% and 10% concentrations.
- The extent of changes indicates the absence of a sensitizing potential of the test substance at concentrations, which lead to skin irritation.
- Based on the results discussed above and applying the evaluation criteria the test substance is considered to be an irritant but not to possess a relevant sensitizing potential.
- This evaluation is corroborated by the minimal lymph node response and the experience, that even sensitizers with moderate potency, e.g. the positive control hexylcinnamaldehyde produce relevant lymph node responses in irritating concentrations.
- Higher concentrations were not tested, because the concentrations tested produced ear skin irritation.
- Thus, it is concluded that the test substance does not have a sensitizing effect in the mouse Local Lymph Node Assay under the test conditions chosen.