3-phenyl-L-alanine

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

Title:

Unnamed

Year:

2010

Report date:

2010

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of study:

mouse local lymph node assay (LLNA)

Test material

Test material information

Constituent 1

Reference substance name:

D-(-)-α-phenylglycine

EC Number:

212-876-3

EC Name:

D-(-)-α-phenylglycine

Cas Number:

875-74-1

Molecular formula:

C8H9NO2

IUPAC Name:

(2R)-2-amino-2-phenylacetic acid

In vivo test system

Test animals

Species:

mouse

Strain:

CBA

Sex:

female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan Laboratories B.V. (The Netherlands)
- Age at study initiation: 8 - 12 weeks
- Weight at study initiation: 19.4 to 23.6 g
- Housing: single
- Diet: pelleted standard diet, ad libitum
- Water: tap water, ad libitum
- Acclimation period: at least 5 days prior to the start of dosing under test conditions

ENVIRONMENTAL CONDITIONS
- Temperature: 22 +/- 2°C
- Humidity: 45-65%
- Air changes: data not available
- Photoperiod: artificial light 6.00 a.m. - 6.00 p.m.

Study design: in vivo (LLNA)

Vehicle:

propylene glycol

Concentration:

5, 10, and 25%

No. of animals per dose:

4 females per group

Details on study design:

RANGE FINDING TESTS:
- Compound solubility:
A solubility experiment was performed according to the recommendations given by OECD 429. The highest test item concentration, which can be technically used was a 25 % suspension in propylene glycol.
- Irritation:
To determine the highest non-irritant test concentration, a pre-test was performed in two animals. Two mice were treated with concentrations of 10 and 25% each on three consecutive days. In the pre-test clinical signs were recorded within 1 hour and 24 ± 4 hours after each application as well as on day 7. At the tested concentrations the animals did not show any signs of irritation or systemic toxicity.
- Lymph node proliferation response: not determined.

MAIN STUDY
ANIMAL ASSIGNMENT AND TREATMENT
- Name of test method: LLNA
- Criteria used to consider a positive response:
A test item is regarded as a sensitiser in the LLNA if the following criteria are fulfilled:
> First, that exposure to at least one concentration of the test item resulted in an incorporation of 3HTdR at least 3-fold or greater than that recorded in control mice, as indicated by the stimulation index.
> Second, that the data are compatible with a conventional dose response, although allowance must be made (especially at high topical concentrations) for either local toxicity or immunological suppression.

TREATMENT PREPARATION AND ADMINISTRATION:
Each test group of mice was treated by topical (epidermal) application to the dorsal surface of each ear (left and right) with different test item concentrations of 5, 10, and 25% (w/v) in propylene glycol. The application volume, 25 µl, was spread over the entire dorsal surface (diameter ca. 8 mm) of each ear once daily for three consecutive days. A further group of mice was treated with an equivalent volume of the relevant vehicle alone (control animals).
Five days after the first topical application, all mice were administered with 250 µl of 81.9 µCi/ml 3HTdR (corresponds to 20.5 µCi 3HTdR per mouse) by intravenous injection via a tail vein.
Approximately five hours after treatment with 3HTdR all mice were euthanised.
The draining lymph nodes were rapidly excised and pooled per group (8 nodes per group). Single cell suspensions were prepared.
The level of 3HTdR incorporation was then measured on a beta-scintillation counter.

Positive control substance(s):

hexyl cinnamic aldehyde (CAS No 101-86-0)

Results and discussion

Positive control results:

EC3 = 12.9 % (positive)

In vivo (LLNA)

Results

Results 1

Key result

Parameter:

SI

Value:

1.53

Test group / Remarks:

5%

Results 2

Key result

Parameter:

SI

Value:

2.52

Test group / Remarks:

10%

Results 3

Key result

Parameter:

SI

Value:

2.45

Test group / Remarks:

25%

Any other information on results incl. tables

No deaths occurred during the study period.

No symptoms of local toxicity at the ears of the animals and no systemic findings were observed during the study period.

The body weight of the animals, was within the range commonly recorded for animals of this strain and age.

 

Table 1: results

Vehicle: propylene glycol

Test item concentration % (w/v)	Group	Measurement DPM	Calculation			Result
			DPM-BG^a)	number of lymph nodes	DPM per lymph node^b^)	S.I.
---	BG I	30	---	---	---	---
---	BG II	15	---	---	---	---
---	1	1496	1474	8	184.2
5	2	2271	2249	8	281.1	1.53
10	3	3733	3711	8	463.8	2.52
25	4	3626	3604	8	450.4	2.45

BG =  Background (1 ml 5% trichloroacetic acid) in duplicate

1    =  Control Group

2-4=  Test Group

S.I. =  Stimulation Index

^a)   =  The mean value was taken from the figures BG I and BG II

^b)    =  Since the lymph nodes of the animals of a dose group were pooled, DPM/node was determined by dividing the measured value by the number of lymph nodes pooled

The EC3 value could not be calculated, since all S.I.´s are below 3.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The test item D(-)alpha-Phenylglycine is not a skin sensitiser under the described conditions.

Executive summary:

In the study the test item D(-)alpha-Phenylglycine suspended in propylene glycol was assessed for its possible contact allergenic potential (OECD 429, GLP).

For this purpose a local lymph node assay was performed using test item concentrations of 5, 10, and 25%.

The animals did not show any clinical signs during the course of the study and no cases of mortality were observed.

In this study Stimulation Indices (S.I.) of 1.53, 2.52, and 2.45 were determined with the test item at concentrations of 5, 10, and 25% in propylene glycol, respectively.

The test item D(-)alpha-Phenylglycine is not a skin sensitiser in this assay.