Registration Dossier

Data platform availability banner - registered substances factsheets

Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Administrative data

Endpoint:
skin sensitisation: in vivo (non-LLNA)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
28 July - 29 August 1998
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1999
Report date:
1999

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
EU Method B.6 (Skin Sensitisation)
Qualifier:
according to guideline
Guideline:
OECD Guideline 406 (Skin Sensitisation)
Qualifier:
according to guideline
Guideline:
other: Magnusson, B. and Kligman, A.M. (1970) Allergic Contact Dermatitis in the Guinea-pig: Identification of contact allergens, Thomas, C.C., Springfield, Illinois, U.S.A.
GLP compliance:
yes (incl. QA statement)
Type of study:
guinea pig maximisation test
Justification for non-LLNA method:
MAGNUSSON, B. and KLIGMAN, A.M. (1970) Allergic Contact Dermatitis in the Guineapig: Identification of contact allergens, Thomas, C.C., Springfield, Illinois, U.S.A.

Test material

Constituent 1
Reference substance name:
4-chloro-6-ethyl-5-fluoropyrimidine; dichloromethane
EC Number:
929-144-0
IUPAC Name:
4-chloro-6-ethyl-5-fluoropyrimidine; dichloromethane
Test material form:
liquid
Details on test material:
Clear yellow liquid
Storage conditions: Room temperature in the dark
Specific details on test material used for the study:
Clear yellow liquid
Storage conditions: room temperature in the dark
Batch No: 5494/95/2
Purity: 96.5%

In vivo test system

Test animals

Species:
guinea pig
Strain:
Dunkin-Hartley
Sex:
female
Details on test animals and environmental conditions:
The animals were approximately four to seven weeks of age on arrival and were acclimatised to the experimental environment for six days prior to the start of the main study. The guinea-pigs were within the weight range 353 - 399 g at the start of the study (Day 1).
Additional animals from the same supplier were used for the preliminary investigations.
The animals on the main study were allocated without conscious bias to two groups as follows:
Group Number of Animal animals numbers
Control animals 5 3155 to 3159
Test animals 10 3160 to 3169

The guinea-pigs were housed in groups of five in suspended metal cages with wire mesh floors.
A vitamin C enriched guinea-pig diet and drinking water were provided ad libitum. Hay was given thrice weekly.
Animal room temperature was controlled within the range 18 to 30°C and relative humidity within the range 33 to 80%.
Lighting was controlled by means of a time switch to give 12 hours of artificial light (0700 - 1900 hours) in each 24 hour period.
Each animal was identified by ear tattoo number.

Study design: in vivo (non-LLNA)

Inductionopen allclose all
Route:
intradermal
Concentration / amount:
Freund's complete adjuvant was diluted with an equal volume of water for irrigation (PH. Eur.)
Day(s)/duration:
one injection
Adequacy of induction:
not specified
Route:
intradermal
Vehicle:
other: Alembicol D
Concentration / amount:
UK-103,444, 2.5% v/v in Alembicol D
Day(s)/duration:
one injection
Adequacy of induction:
highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically
Route:
intradermal
Vehicle:
other: Freund's completea djuvant and Alembicol D
Concentration / amount:
UK-103,444, 2.5% in a 50 : 50 mixture of Freund's complete adjuvant and Alembicol D.
Day(s)/duration:
one injection
Adequacy of induction:
not specified
Route:
epicutaneous, semiocclusive
Vehicle:
other: Alembicol D
Concentration / amount:
A 20 x 40 mm patch of Whatman No. 3 paper was saturated with approximately 0.4 ml of UK-
103,444, 10% v/v in Alembicol D.
Day(s)/duration:
one week after injections and was left in place for 48 hours
Adequacy of induction:
not specified
Challenge
Route:
epicutaneous, semiocclusive
Vehicle:
other: Alembicol D
Concentration / amount:
A 20 x 20 mm patch of Whatman No. 3 paper was saturated with approximately 0.2 ml of
UK-103,444, 1% v/v in Alembicol D and applied to an anterior site on the flank. UK-103,444,
0.5% v/v in Alembicol D was applied in a similar manner to the posterior site.
Day(s)/duration:
The control and test animals were challenged topically two weeks after the topical induction application using UK-103,444, 1 and 0.5% v/v in Alembicol D. These new patches were left on for 24 hours.
Adequacy of challenge:
highest non-irritant concentration
No. of animals per dose:
5 control and 10 test animals (15 total)
Details on study design:
Preliminary study:
The intradermal and topical irritancy of a range of dilutions of the test substance was investigated to identify where possible (a) concentrations of the test substance that would produce irritation suitable for the induction phase of the main study and (b) a maximum non-irritant concentration by the topical route of administration for the challenge phase.
The animals for the topical irritancy investigations were pre-treated with an intradermal injection of Freund's complete adjuvant, 50 : 50 with water for irrigation (Ph.Eur.), approximately one week prior to the start of the preliminary investigations.

Selection of concentrations of test substance for the main study:
Based on the results of the preliminary investigations, the following concentrations of UK-103,444 were selected:
Induction intradermal injection - 2.5% v/v in Alembicol D
This was the highest concentration that caused irritation but did not adversely affect the animals.
Induction topical application - 10% v/v in Alembicol D
This was the highest concentration that produced some irritation but did not adversely affect the animals.
Topical challenge - 1 and 0.5% v/v in Alembicol D
From preliminary investigations 1% v/v in Alembicol D was the highest concentration not giving rise to irritating effects.

Main study:
The procedure may be considered in two parts, Induction and Challenge.
Induction:
Induction intradermal injections - test animals
A 40 x 60 mm area of dorsal skin on the scapular region of the guinea-pig was clipped free of hair with electric clippers. Three pairs of intradermal injections were made into a 20 x 40 mm area within the clipped area.
Injectables for the test animals were prepared as follows:
1. Freund's complete adjuvant** was diluted with an equal volume of water for irrigation (Ph.Eur.).
2. UK-103,444, 2.5% v/v in Alembicol D.
3. UK-103,444, 2.5% v/v in a 50 : 50 mixture of Freund's complete adjuvant and Alembicol D.

Induction topical application - test animals:
One week after the injections, the same 40 x 60 mm interscapular area was clipped and shaved free of hair.
A 20 x 40 mm patch of Whatman No. 3 paper was saturated with approximately 0.4 ml of UK- 103,444, 10% v/v in Alembicol D. The patch was placed on the skin of the test animals and covered by a length of impermeable plastic adhesive tape (50 mm width "Blenderm"). This in
turn was firmly secured by elastic adhesive bandnge (50 mm width "Elastoplast") wound round the torso of the animal and fixed with "Sleek" impervious plastic adhesive tape. The dressing was left in place for 48 hours.
Induction - control animals:
During the induction phase, the control animals were treated similarly to the test animals with the exception that the test substance was omitted from the intradermal injections and topical application.

Challenge:
Challenge - control and test animals
The control and test animals were challenged topically two weeks after the topical induction application using UK-103,444, 1 and 0.5% v/v in Alembicol D.
Hair was removed by clipping and then shaving from an area on the left flank of each guinea-pig. A 20 x 20 mm patch of Whatman No. 3 paper was saturated with approximately 0.2 ml of UK-103,444, 1% v/v in Alembicol D and applied to an anterior site on the flank. UK-103,444,
0.5% v/v in Alembicol D was applied in a similar manner to the posterior site. The patches were sealed to the flank for 24 hours under strips of "Blenderm" covered by "Elastoplast" wound round the trunk and secured with "Sleek".

Challenge controls:
5 controls
Positive control substance(s):
yes
Remarks:
2-Mercaptobenzothiazole (MBT)

Results and discussion

Positive control results:
INDUCTION
Intradermal injections - Slight to well-defined irritation was seen in test animals at sites receiving MBT, 10% w/v in Alembicol D and slight irritation was observed in control animals receiving Alembicol D.
Topical application - Well-defined erythema was observed in test animals following topical application with MBT, 83.3% w/v in Alembicol D. Well-defined erythema was seen in the control animals receiving Alembicol D.
CHALLENGE
Dermal reactions were noted in all of the ten test animals compared to none in the controls therefore all ten test animals were considered to have given positive sensitization responses.
CONCLUSION
In this study MBT produced evidence of skin sensitisation (delayed contact hypersensitivity) in all of the ten animals, thus confirming the sensitivity and reliability of the experimental technique.

In vivo (non-LLNA)

Resultsopen allclose all
Key result
Reading:
2nd reading
Hours after challenge:
48
Group:
test chemical
Dose level:
Anterior site, exposed to UK-103,444, 1% v/v in Alembicol D P Posterior site, exposed to UK-103,444, 0,5% v/v in Alembicol D
No. with + reactions:
5
Total no. in group:
10
Clinical observations:
The reactions seen in five of the test animals were more marked than those observed for the control animal, therefore these gave positive response. The remaining test animals gave negative responses.
Remarks on result:
positive indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
negative control
No. with + reactions:
0
Total no. in group:
5
Clinical observations:
none
Remarks on result:
no indication of skin sensitisation
Reading:
2nd reading
Hours after challenge:
48
Group:
positive control
Dose level:
83.3% MBT topical and 10% intradermal injection
No. with + reactions:
10
Total no. in group:
10

Applicant's summary and conclusion

Interpretation of results:
Category 1 (skin sensitising) based on GHS criteria
Conclusions:
In this study UK-103,444 produced evidence of skin sensitization (delayed contact hypersensitivity) in five of the ten test animals, the remaining five animals gave negative responses. Overall UK-103,444 is considered to have the potential to cause skin sensitization.
Executive summary:

UK-103,444 requires labelling with the risk phrase of GHS classification of Skin Sens. category 1, H-317: "May cause an allergic skin reaction".