1-benzyl-5-phenylbarbituric acid

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2018-03-08 - 2018-04-13

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2018

Report date:

2018

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of study:

Buehler test

Justification for non-LLNA method:

Test was sponsored by supplier in India. Since no other data is available no new animal study was performed.

Test material

Test material information

Constituent 1

Reference substance name:

1-benzyl-5-phenylbarbituric acid

EC Number:

276-940-2

EC Name:

1-benzyl-5-phenylbarbituric acid

Cas Number:

72846-00-5

Molecular formula:

C17H14N2O3

IUPAC Name:

1-benzyl-5-phenylpyrimidine-2,4,6(1H,3H,5H)-trione

Test material form:

solid: particulate/powder

Specific details on test material used for the study:

Molecular Formula
:
C17H14N2O3
Molecular Weight
:
294.3
Characteristics (Physical Appearance)
:
White powder
CAS No.
:
72846-00-5
Batch Number
:
170240
Purity
:
99.5%

In vivo test system

Test animals

Species:

guinea pig

Strain:

Hartley

Sex:

male

Details on test animals and environmental conditions:

Animal Species
and rationale for selection:
Guinea pig (Cavia porcellus); Guinea pig has been the animal of choice for predictive Sensitisation tests, and is the species preferred by the regulatory guidelines.
Strain and rationale for selection:
English (Hartley); The strain has been selected due to its availability in requisite numbers.
Source:
Sri Raghavendra Enterprises, Bangalore, INDIA
Age at the start of the study:
13 to 14 weeks
Sex:
Male
Body weight range (Day -1):
426 g to 513 g
Number of animals used:
Pilot Study - 2 animals;
Main study - 30 animals;
(Treatment group - 20 animals; Control group - 10 animals)
Veterinary Examination:
Prior to final assignment to the study, the animals were subjected to a veterinary examination to ensure that the selected guinea pigs were in a good state of health.
Environmental conditions : The room was climatically controlled with 10 to 15 air changes per hour. The room was air conditioned with temperature between 17 to 23 °C, relative humidity 30 to 70% and illumination cycle set to 12 hours light and 12 hours dark.

Study design: in vivo (non-LLNA)

Induction

Route:

epicutaneous, occlusive

Vehicle:

other: analytical grade water with 0.2% Tween 80

Concentration / amount:

33%

Day(s)/duration:

day 0,7,14

Adequacy of induction:

highest concentration used causing mild-to-moderate skin irritation and well-tolerated systemically

Challenge

No.:

#20

Route:

epicutaneous, occlusive

Vehicle:

other: grade water with 0.2% Tween 80

Concentration / amount:

33%

Day(s)/duration:

4 weeks

Adequacy of challenge:

highest non-irritant concentration

No. of animals per dose:

20

Details on study design:

INDUCTION PROCEDURES
Approximately 24 hours before treatment, the hair on the left flank was closely clipped with an electric clipper exposing an area of approximately 80 cm2 (8 x 10 cm). The gauze patch (occlusive dressing) admeasuring about 4 to 6 cm2 (at least 2 cm x 2 cm), fully loaded with formulated test item (treatment group) and vehicle control group (Analytical grade water with 0.2% Tween 80) was applied to the prepared area and was covered with an aluminum foil and secured in position with an adhesive tape wound around the torso for a period of 6 hours. After 6 hours contact period the test patch was removed and skin was wiped with analytical grade water and dried. The skin reaction was evaluated at 24 and 48 hours after removal of the skin patch by Magnusson and Kligman grading scale (3.6.2).
CHALLENGE PROCEDURES
Treatment group and control group were challenged at 4 weeks after first induction application. The untreated flanks of animals were cleared of hair by close-clipping. The gauze patch fully loaded with 0.5 ml of test item was applied to the posterior part of the untreated (right) flanks of treatment and control group animals. The procedure of application and the exposure period was same as that during the induction.

Challenge controls:

yes

Positive control substance(s):

yes

Remarks:

α-Hexylcinnamaldehyde

Results and discussion

Positive control results:

For induction 40% v/v concentration while for challenge 10% v/v concentration of α-Hexylcinnamaldehyde ≥ 95% was used. Acetone was used as vehicle for purpose of induction as well as challenge. In this test, a positive response was observed in 50% of the tested animals, thereby meeting the requirements specified by OECD Test Guideline No. 406, and classifying the positive control item as a moderate sensitiser.

In vivo (non-LLNA)

Results

Results 1

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

test chemical

Dose level:

33%

No. with + reactions:

0

Total no. in group:

20

Clinical observations:

none

Results 2

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

test chemical

Dose level:

33%

No. with + reactions:

0

Total no. in group:

20

Clinical observations:

none

Results 3

Key result

Reading:

1st reading

Hours after challenge:

24

Group:

negative control

Dose level:

0

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

none

Results 4

Key result

Reading:

2nd reading

Hours after challenge:

48

Group:

negative control

Dose level:

0

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

none

Results 5

Key result

Reading:

1st reading

Hours after challenge:

48

Group:

positive control

Dose level:

10%

No. with + reactions:

5

Total no. in group:

10

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

In this study, based on the results of a pilot study, induction of sensitisation was attempted by exposing the guinea pigs to 33% w/v of 1-Benzyl-5-Phenylbarbituric acid (BPBA) in analytical grade water with 0.2% Tween 80 on days 0, 7 and 14 by epidermal route on the clipped left flank area. After an induction period of 14 days, the animals were similarly subjected to a ‘challenge application’ with 33% w/v of 1-Benzyl-5-Phenylbarbituric acid (BPBA) in analytical grade water 0.2% Tween 80 on day 28 of the study, on their right flank. Treated group comprised of 20 animals and control group comprised of 10 animals.
Skin reaction was recorded at 24 and 48 hours after removal of each induction patch and was also evaluated at 24 and 48 hours after removal of the challenge patch. The guinea pigs were examined for survival and abnormal clinical signs daily during the study, and their body weights were recorded at start and termination of the experiment.
In this study all guinea pigs survived throughout the duration of the study. Clinical observations made periodically during the study revealed that, test item did not induce any signs of systemic toxicity in the exposed animals. There was no adverse effect of the treatment on the body weight gain by the exposed guinea pigs.
Skin Reaction Following Induction Applications
As revealed at 24 and 48 hours after removal of each induction patch for the induction applications made on days 0, 7 and 14, the test item did not induce any skin reaction on the site of application in the treated guinea pigs.
Skin Reaction Following Challenge Application
After challenge application made on day 28, as observed on days 29 and 30, there was no evidence of any acute dermal response at the site of application in the form of erythema and / or swelling in all animals from the control and the treatment groups.
Conclusion
In absence of a sensitisation response in any of the treated animals to challenge by the test item, 1-Benzyl-5-Phenylbarbituric acid (BPBA) is classified as non sensitiser to guinea pigs as per the criteria of classification for the Buehler test (Kimber et. al.,1990).

Executive summary:

In this study, based on the results of a pilot study, induction of sensitisation was attempted by exposing the guinea pigs to 33% w/v of 1-Benzyl-5-Phenylbarbituric acid (BPBA) in analytical grade water with 0.2% Tween 80 on days 0, 7 and 14 by epidermal route on the clipped left flank area. After an induction period of 14 days, the animals were similarly subjected to a ‘challenge application’ with 33% w/v of 1-Benzyl-5-Phenylbarbituric acid (BPBA) in analytical grade water 0.2% Tween 80 on day 28 of the study, on their right flank. Treated group comprised of 20 animals and control group comprised of 10 animals.

Skin reaction was recorded at 24 and 48 hours after removal of each induction patch and was also evaluated at 24 and 48 hours after removal of the challenge patch. The guinea pigs were examined for survival and abnormal clinical signs daily during the study, and their body weights were recorded at start and termination of the experiment.

In this study all guinea pigs survived throughout the duration of the study. Clinical observations made periodically during the study revealed that, test item did not induce any signs of systemic toxicity in the exposed animals. There was no adverse effect of the treatment on the body weight gain by the exposed guinea pigs.

Skin Reaction Following Induction Applications

As revealed at 24 and 48 hours after removal of each induction patch for the induction applications made on days 0, 7 and 14, the test item did not induce any skin reaction on the site of application in the treated guinea pigs.

Skin Reaction Following Challenge Application

After challenge application made on day 28, as observed on days 29 and 30, there was no evidence of any acute dermal response at the site of application in the form of erythema and / or swelling in all animals from the control and the treatment groups.

Conclusion

In absence of a sensitisation response in any of the treated animals to challenge by the test item, 1-Benzyl-5-Phenylbarbituric acid (BPBA) is classified as non sensitiser to guinea pigs as per the criteria of classification for the Buehler test (Kimber et. al.,1990).