Butyl glycollate

Skin sensitisation

Administrative data

Endpoint:

skin sensitisation: in vivo (non-LLNA)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2000-04-11 to 2000-06-11

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2000

Report date:

2000

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 406 (Skin Sensitisation)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.6 (Skin Sensitisation)

Deviations:

no

Test guideline 3

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2600 (Skin Sensitisation)

Deviations:

no

Test guideline 4

Qualifier:

according to guideline

Guideline:

other: MAFF Japan Testing Guidelines Dermal Sensitization

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of study:

guinea pig maximisation test

Justification for non-LLNA method:

The Magnusson-Kligman Maximization Test was common standard at the time the study was conducted.

Test material

Test material information

Constituent 1

Reference substance name:

Butyl glycollate

EC Number:

230-991-7

EC Name:

Butyl glycollate

Cas Number:

7397-62-8

Molecular formula:

C6H12O3

IUPAC Name:

butyl glycolate

Constituent 2

Reference substance name:

Polysolvan O

IUPAC Name:

Polysolvan O

Constituent 3

Reference substance name:

Glycolic acid-n-butyl ester

IUPAC Name:

Glycolic acid-n-butyl ester

Details on test material:

- Name of test material (as cited in study report): H-24386 (butyl glycollate)
- Physical state: liquid
- Analytical purity: 99.07%
- Impurities (identity and concentrations): 0.21% butanol, 0.70% unknown, 0.04% water
- Purity test date: 13 March 2000
- Lot/batch No.: 1
- Expiration date of the lot/batch: 01 February 2002
- Stability under test conditions: stable
- Storage condition of test material: Locked storage cabinet, ambient conditions

In vivo test system

Test animals

Species:

guinea pig

Strain:

Dunkin-Hartley

Sex:

male

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Ace Animals, Boyertown, PA, USA
- Weight at study initiation: 341 - 474 g
- Housing: single, elevated stainless steel cages with wire mesh flooring.
- Diet: ad libitum, standard chow (Purina Certified Guinea Pig Diet #5026)
- Water: ad libitum (tap water)
- Acclimation period: 13 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 17 °C - 32 °C
- Humidity (%): 2% - 83%.
- Photoperiod (hrs dark / hrs light): 12 hrs dark/12 hrs light

Study design: in vivo (non-LLNA)

Induction

Route:

intradermal and epicutaneous

Vehicle:

propylene glycol

Concentration / amount:

Induction:
Intradermal: 1% in propylene glycol, 1.0% in Freund’s adjuvant
Epidermal: 0.5 mL of neat test item

Challenge:
Epidermal: 0.5 mL of 50% (w/v) dilution in propylene glycol, 0.5 ml aliquot of a 1:3 (v/v) dilution of 50% (w/v) dilution in propylene glycol

Re-challenge:
Epidermal: 0.5 mL of 50% (w/v) dilution in propylene glycol

Challenge

Route:

epicutaneous, occlusive

Vehicle:

propylene glycol

Concentration / amount:

Induction:
Intradermal: 1% in propylene glycol, 1.0% in Freund’s adjuvant
Epidermal: 0.5 mL of neat test item

Challenge:
Epidermal: 0.5 mL of 50% (w/v) dilution in propylene glycol, 0.5 mL aliquot of a 1:3 (v/v) dilution of 50% (w/v) dilution in propylene glycol

Re-challenge:
Epidermal: 0.5 mL of 50% (w/v) dilution in propylene glycol

No. of animals per dose:

9 male Guinea pigs for range-finding study
30 male Guinea pigs for the induction study (20 males for test item induction, 10 males for vehicle induction)

Details on study design:

RANGE FINDING TESTS:
Intradermal dose range finding:
The intradermal irritation potential of the test article was evaluated by exposing 3 naive animals to six 0.1 mL injections: three injections of three separate concentrations (1.0, 3.0, and 5.0%) prepared in propylene glycol and three injections of the identical concentrations (1.0, 3.0, and 5.0%) in Freund's Adjuvant. The injections were made sufficiently deep into the dermis to minimize sloughing. Paired injections of the same concentrations of H-24386that were formulated in different vehicles were made in the skin overlying the scapulae, each pair flanked the dorsal midline. The sites were left uncovered and scored at the 24 and 48 h.

Topical dose range finding:
The topical irritation potential of the test article was evaluated by exposing a group of three naive animals to two individual concentrations in propylene glycol.

A 0.5 mL portion of H-24386 was absorbed onto an approximate 20 x 45 mm patch and applied to the left flank of each animal. A 0.5 mL aliquot of a 50% w/v dilution in propylene glycol (considered 50%) was like wise applied to the opposite flank of each animal. The patches were covered with an occlusive plastic wrap and then covered with elastic bandage for approximately 48 hours. The sites were unwrapped, the sites cleaned with propylene glycol and then with deionized water. Approximately three hours and 24 hours after unwrapping, the sites were scored.

MAIN STUDY
A. INDUCTION EXPOSURE
- No. of exposures: paired 0.1 ml intradermal injection to clipped skin. (anterior, middle, posterior sites) on day 1
- Exposure period: 7 days
- Test groups: 1 (20 animals)
- Control group: 1 (10 animals)
- Site: Intradermal: anterior, middle, posterior into the skin overlaying each scapula; epidermal: Intradermal injection sites
- Frequency of applications: Intradermal induction: day 1, epidermal induction: day 8
- Concentrations: Intradermal: 1% in propylene glycol, 1.0% in Freund’s adjuvant
Epidermal: 0.5 mL of neat test item

B. CHALLENGE EXPOSURE
- No. of exposures: single, paired applications
- Day(s) of challenge: day 22
- Test groups: 1 (20 animals)
- Control group: 1 (10 animals)
- Site: clipped skin of left and right flank
- Concentrations: Epidermal: 0.5 ml of 50% (W/V) dilution in propylene glycol, 0.5 ml aliquot of a 1:3 (V/V) dilution of 50% (W/V) dilution in propylene glycol
- Evaluation (hr after challenge): 24 and 48 h

C. RE-CHALLENGE EXPOSURE
- No. of exposures: single paired applications
- Day(s) of re-challenge: day 29
- Test groups: 1 (20 animals)
- Control group: 1 (10 animals)
- Site: clipped skin of left and right flank
- Concentrations: Epidermal: 0.5 mL of 50% (w/v) dilution in propylene glycol
- Evaluation (hours after challenge): 24 and 48 hours

Challenge controls:

Both, test and vehicle controls were challenged as described above.

Positive control substance(s):

yes

Remarks:

alpha-hexylcinnamaldehyde (not directly tested in the study but within the validation of the Magnusson-Kligman Maximization Test)

Results and discussion

In vivo (non-LLNA)

Results

Results 1

Reading:

other: details are provided in tables below (see remarks on results including tables and figures).

Hours after challenge:

48

Group:

test chemical

Dose level:

50% w/v in propylene glycol

No. with + reactions:

0

Total no. in group:

20

Clinical observations:

details are provided in tables below (see remarks on results including tables and figures).

Remarks on result:

other: Net incidence of sensitization, details are provided in tables below (see remarks on results including tables and figures below

Results 2

Reading:

other: details are provided in tables below (see remarks on results including tables and figures).

Hours after challenge:

48

Group:

negative control

Dose level:

100%

No. with + reactions:

0

Total no. in group:

10

Clinical observations:

details are provided in tables below (see remarks on results including tables and figures).

Remarks on result:

other: Net incidence of sensitization, details are provided in tables below (see remarks on results including tables and figures below

Results 3

Reading:

other: details are provided in tables below (see remarks on results including tables and figures).

Hours after challenge:

48

Group:

positive control

Dose level:

5% alpha-hexylcinnamaldehyde w/v in 95% ethanol

No. with + reactions:

8

Total no. in group:

20

Clinical observations:

details are provided in tables below (see remarks on results including tables and figures).

Remarks on result:

other: Net incidence of sensitization, details are provided in tables below (see remarks on results including tables and figures below

Any other information on results incl. tables

Topical Challenge Scores, Group I - Test substance

Animal No.	Left Flank Anterior Site A 24 Hours            48 Hours		Left Flank Posterior Site B 24 Hours            48 Hours		Right Flank Site C 24 Hours            48 Hours
1	0	OH	0	0	0	0
2	OK	OK	0	0	0	0
3	OK	OK	0	0	0	0
4	OH	OH	0	0	0	0
5	0	0	0	0	0	0
6	0	0.5	0	0	0	0
7	0	0	0.5	0.5	0	0
8	0	0	0	0	0	0
9	0	0	0	0	0	0
10	0	1H	0	0	0	0
11	0	0	0	0	0	0
12	0	0	0	0	0	0
13	1	0.5H	0	0	0	0
14	0	OH	0	0	0	0
15	2	IH	0	0	0	0
16	0	IH	0	0	0	0
17	0	0	0	0	0	0
18	0	OH	0	0	0	0
19	0	0	0	0	0	0
20	2H	2H	0	0	0	0

Site A = Each patch received 0.5 ml of 50% w/v H-24386 in propylene glycol

Site B = Each patch received 0.5 ml of a 1:3 v/v dilution of 50% H-24386 in propylene glycol Site C = Each patch received 0.5 ml of propylene glycol

Note: Times represent hours alter unwrapping.

H = Hyperkeratosis

K = Exfoliation Topical Challenge Scores, Group II - Vehicle and Test substance Irritation Control

Study Animal Number	Left Flank Anterior Site A 24 Hours            48 Hours		Left Flank Posterior Site B 24 Hours            48 Hours		Right Flank Site C 24 Hours            48 Hours
21	0	0	0	0	0	0
22	0	0	0	0	0	0
23	0	0	0	0	0	0
24	0	0	0	0	0	0
25	2K	2K	0	1K	0	0
26	0	0	0	0	0	0
27	0	0	0	0	0	0
28	0	0	0	0	0	0
29	0	OH	0	0	0	0
30	0	0	0	0	0	0

Site A = Each patch received 0.5 ml of 50% w/v H-24386 in propylene glycol

Site B = Each patch received 0.5 ml of a 1:3 v/v dilution of 50% H-24386 in propylene glycol Site C = Each patch received 0.5 ml of propylene glycol

H = Hyperkeratosis

K = Exfoliation

Note: Times represent hours after unwrapping

Topical Re-challenge Scores - Group I - Test substance

Animal No.	Site Location	24 Hours t	48 Hours t
1	P	OH	OH
2	P	OH	0
3	P	0	0
4	P	0	0
5	P	0.5H	0.5H
6	P	OH	OH
7	P	0.5	0
8	P	0	0
9	P	0	0
10	P	M	M
11	P	0	0
12	P	1H	0.5H
13	P	0	0
14	P	0	0
15	P	0	0
16	P	0.5H	0.5H
17	P	0	0
18	P	0	0
19	P	0	OH
20	P	0	0

Site D = Each patch received 0.5 ml of 50% w/v H-24386 in propylene glycol P = Patch site posterior to Site C

H = Hyperkeratosis

M = The test article/patch was dislodged during the exposure period. t Note: Times represent hours after unwrapping. Topical Re-challenge Scores - Group I - Test substance

Animal No.	Site Location	24 Hours t	48 Hours t
1	P	OH	OH
2	P	OH	0
3	P	0	0
4	P	0	0
5	P	0.5H	0.5H
6	P	OH	OH
7	P	0.5	0
8	P	0	0
9	P	0	0
10	P	M	M
11	P	0	0
12	P	1H	0.5H
13	P	0	0
14	P	0	0
15	P	0	0
16	P	0.5H	0.5H
17	P	0	0
18	P	0	0
19	P	0	OH
20	P	0	0

Site D = Each patch received 0.5 mL of 50% w/v H-24386 in propylene glycol P = Patch site posterior to Site C

H = Hyperkeratosis

M = The test article/patch was dislodged during the exposure period. t Note: Times represent hours after unwrapping. Topical Re-challenge Scores - Group II - Vehicle and Test Article Irritation Control

		Right Flank Posterior Site D
Animal No.	Site Location	24 Hours t	48 Hours t
21	P	0	0
22	P	M	M
23	P	1H	0.5H
24	P	0	0
25	P	OH	OH
26	P	0	0
27	P	0	0
28	P	OK	OK
29	P	0	OK
30	P	0	OK

Site D = Each patch received 0.5 mL of 50% w/v H-24386 in propylene glycol P = Patch site posterior to Site C

H = Hyperkeratosis

K = Exfoliation

M = The test article/patch was dislodged during the exposure period.

t Note: Times represent hours alter unwrapping.

Applicant's summary and conclusion

Interpretation of results:

not sensitising

Remarks:

Migrated information

Conclusions:

Under the conditions of this study, 0.5 mL of a 50% w/v dilution of Polysolvan O (butyl glycollate) in propylene glycol or a 1:3 v/v dilution of 50% the test substance in propylene glycol is not considered to be a dermal sensitizer in guinea pigs.

Executive summary:

The potential of Polysolvan O (butyl glycollate, 99.07%) to produce dermal sensitization in guinea pigs was assessed by the Magnusson-Kligman Maximization Test. Twenty animals were intradermally induced with a 1.0% concentration of the test article in propylene glycol and in Freund's Adjuvant and topically induced with 0.5 mL of test article (considered 100%). The animals were challenged with 0.5 mL of a 50% w/v dilution of the test article in propylene glycol, a 1:3 v/v dilution of a 50% dilution of the test article in propylene glycol and 0.5 mL of propylene glycol.

Due to equivocal challenge scores at all challenge sites treated with the test article, the animals were re-challenged with 0.5 mL of a 50% w/v dilution of the test article in propylene glycol. The same procedures were conducted using a control group consisting of 10 animals, except that the test article was replaced with propylene glycol during induction. These animals were challenged and re-challenged in the same manner as the test article animals. This study is assessed as appropriate and valid since it was performed according to an internationally accepted testing guideline and according to GLP. Reporting, assessment and data presentation in the study report was considered as appropriate.

 

Observations of no redness to moderate redness, were noted at 24 and 48 hours with two instances of exfoliation and two instances of hyperkeratosis noted at 24 hours and two instances of exfoliation and nine instances of hyperkeratosis at 48 hours after unwrapping for animals induced with Polysolvan O (butyl glycollate, 99.07%) as described above and challenged with 0.5 mL of 50% w/v test substance in propylene glycol. The incidence of response was 25% (5/20). The 1:3 v/v dilution of 50% test substance in propylene glycol produced no redness to barely perceptible redness at 24 and 48 hours after the challenge unwrapping. The incidence of response was 5% (1/20). The net incidence was 0% (0/20) based on the vehicle and test article irritation control challenge scores (see below). The vehicle did not produce any dermal irritation.

All test article animals appeared to be normal throughout the study except for the following exceptions. Animal #8 exhibited labored breathing, rales and a rapid heart rate following dosing on Day 1, which reverted to normal within 100 minutes. Animal # 19 appeared emaciated on Day 7 with slight improvement on Day 8 and fall recovery on Day 9. Two animals (#12 and #19) exhibited weight losses between Days -1 and 7. Two animals (# 1 and #20) exhibited a weight loss between Days 7 and 14. One animal (#4) exhibited a weight loss between Days 14 and 21. Two animals (# 10 and # 16) exhibited a weight loss between Days 21 and 28. One animal (#11) did not gain weight between Days 28 and 32. All animals exhibited an overall gain in body weight during the study. There were no statistically significant differences identified between the individual body weight percentage gains of the test article group and the vehicle and test article irritation control group.

Observations of no redness to moderate redness were noted at the test article irritation control sites at 24and 48 hours after unwrapping for animals induced with propylene glycol and challenged with 0.5 mL of 50% w/v test substance in propylene glycol. There was one instance of exfoliation at 24 and 48 hours and one instance of hyperkeratosis at 48 hours. No redness was observed at the test article irritation control sites dosed with 0.5 mL of the 1:3 v/v dilution of 50% w/v test substance in propylene glycol at 24 hours, and no redness to scattered mild redness was noted at 48 hours after the challenge unwrapping. The vehicle did not produce any dermal irritation or sensitization All vehicle and test article irritation control animals (10/10) appeared to be normal throughout the study except for the following exceptions. Animals #22, and #24 appeared emaciated on Day 7 with #22showing big improvement on Day 8, and both animals exhibiting full recovery on Day 9. Three animals(#22, #23 and #24) exhibited losses in body weight between Days -1 and 7. Four animals (#25, #27, #28and #29) exhibited losses in body weight between Days 7 and 14. One animal (#28) exhibited a loss in body weight between Days 21 and 28. One animal (#21) exhibited a loss in body weight and one animal(#28) exhibited no weight gain between Days 28 and 32. All animals exhibited an overall gain in bodyweight during the study. There were no statistically significant differences identified between the individual body weight percentage gains of the test article group and vehicle and test article irritation control group.

Due to the equivocal nature of irritation scores at all challenge sites treated with the test article, are challenge was performed. Re-challenge with 0.5 mL of a 50% w/v dilution of test substance in propylene glycol produced no redness to scattered mild redness at 24 hours and no redness to barely perceptible redness at 48 hours after unwrapping in the animals induced with test substance. There were six instances of hyperkeratosis at 24 hours and six instances at 48 hours. The patch on one animal was dislodged during the exposure period and was not scored or used in calculations. No redness to scattered mild redness was noted at 24 hours and no redness to barely perceptible redness at 48 hours in the vehicle and test article irritation control animals similarly re-challenged. There was one instance of exfoliation and two instances of hyperkeratosis at 24 hours and three instances of exfoliation and two instances of hyperkeratosis at 48 hours. The patch on one animal was dislodged during the exposure period and was not scored or used in calculations. The response incidence was 5% (1/19) in the test article induced animals. The net incidence was 0% (0/19) in the test article induced animals based on the vehicle and test article irritation control challenge scores.

Conclusion:

Under the conditions of this study, 0.5 mL of a 50% w/v dilution of Polysolvan O (butyl glycollate) in propylene glycol or a 1:3 v/v dilution of 50% the test substance in propylene glycol is not considered to be a dermal sensitizer in guinea pigs. On the basis of the nature of effects observed in this study and according to the guide for the labeling of dangerous substances, the test substance does not require labeling as a dermal sensitizer.