Dibutyl terephthalate

Sensitisation data (human)

Administrative data

Endpoint:

sensitisation data (humans)

Type of information:

experimental study

Adequacy of study:

key study

Study period:

Applications were made three (3) times per week for three (3) weeks; challenge was done two (2) weeks after final induction application.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: The study was conducted according to acceptable scientific methodology and according to Good Clinical Practices and standard operating procedures and applicable protocols of the testing facility.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2006

Report date:

2006

Materials and methods

Type of sensitisation studied:

skin

Study type:

study with volunteers

Test guideline

Qualifier:

no guideline available

Deviations:

not specified

Principles of method if other than guideline:

To determine the potential of the test material to induce primary or cumulative irritation and/or allergic contact sensitization by repetitive epidermal contact, the test material was evaluated in 208 subjects. Approximately 0.2 mL of test material was applied to the absorbent pad portion of an adhesive dressing and applied to the upper back between the scapulae to form an occlusive patch. Patches were applied three (3) times per week to the same site for a total of nine (9) applications. Patches were removed after 24 hours. Scoring of each patch area was made just prior to re-application. Rest periods consisted of 24 or 48 hours following patch removal. Approximately two (2) weeks after the final induction patch application, a challenge patch was applied to a virgin test site adjacent to the original induction patch site, following the same procedure described for induction. The challenge site was scored following patch removal at 24 and 72 hours post-application.

GLP compliance:

yes

Remarks:

The study was conducted according to Good Clinical Practices (GCPs), a set of international and scientific quality standards for the conduct of testing involving human subjects.

Test material

Test material information

Constituent 1

Reference substance name:

1,4-Benzenedicarboxylic acid, 1,4-dibutyl ester

IUPAC Name:

1,4-Benzenedicarboxylic acid, 1,4-dibutyl ester

Constituent 2

Reference substance name:

Dibutyl terephthalate

EC Number:

217-803-9

EC Name:

Dibutyl terephthalate

Cas Number:

1962-75-0

Molecular formula:

C16H22O4

IUPAC Name:

1,4-dibutyl benzene-1,4-dicarboxylate

Constituent 3

Reference substance name:

Dibutyl benzene-1,4 dicarboxylate

IUPAC Name:

Dibutyl benzene-1,4 dicarboxylate

Constituent 4

Reference substance name:

Terephthalic acid, dibutyl ester; Di-butyl terephthalate; Dibutylterephthalate; DBT

IUPAC Name:

Terephthalic acid, dibutyl ester; Di-butyl terephthalate; Dibutylterephthalate; DBT

Details on test material:

Test material: Dibutyl terephthalate
Lot #: X29455-078-01
Source of test substance: Eastman Chemical Co.
Storage of test material: ambient temperature and humidity in original containers

Method

Type of population:

general

Ethical approval:

confirmed and informed consent free of coercion received

Subjects:

Two hundred twenty-five (225) qualified subjects, male and female, ranging in age from 16 to 79 years, were selected for the evaluation. Two hundred eight (208) subjects completed the study. The remaining subjects discontinued their participation for various reasons, none of which were related to application of the test material.

Clinical history:

To be included in the study, subjects had to: be age 16 (with parental or guardian consent) or older; be free from any visible skin disease which might be confused with a skin reaction from the test material; not have used topical or systemic steroids and/or antihistamines for at least seven days prior to study initiation; complete a Medical History form and understand and sign an Informed Consent form; and be considered reliable and capable of following directions. Subjects were excluded from participation if: they were in ill health; they were under a doctor’s care or taking medication(s) which could influence the results of the study; they were females who were pregnant or nursing; or they had a history of adverse reactions to cosmetics or other personal care products.

Controls:

No

Route of administration:

dermal

Details on study design:

The test material was evaluated in 208 subjects. The upper back between the scapulae served as the treatment area. Approximately 0.2 mL of test material was applied to the absorbent pad portion of an adhesive dressing which was applied to form an occlusive patch. Patches were applied three (3) times per week (e.g., Monday, Wednesday, Friday) to the same site for a total of nine (9) applications. The site was marked to ensure the continuity of patch application. Patches were removed after 24 hours. Following supervised removal and scoring of the first induction patch, participants were instructed to remove subsequent induction patches at home, 24-hours after application. Future evaluations of the patch site were made again just prior to re-application. If a participant was unable to report for an assigned test day, one (1) makeup day was permitted. This day was added to the induction period. If any test site exhibited a moderate (2-level) reaction during induction, application was moved to an adjacent area. Applications were discontinued for the remainder of this test phase, if a moderate (2-level) reaction was observed on this new test site or if marked (3-level) or severe (4-level) reactivity was noted.

Approximately two (2) weeks after the final induction patch application, a challenge patch was applied to a virgin test site adjacent to the original induction patch site, following the same procedure described for induction. The challenge site was scored following patch removal at 24 and 72 hours post-application.

Results and discussion

Results of examinations:

For the 208 subjects that completed the study, 1 had a score of 2 following the 1st induction. Subsequent applications were moved to an adjacent site. For this person, the next 4 applications resulted in a score of 0 followed by a single response of 1. All other applications during induction and challenge for this and all other participants resulted in an evaluation score of 0.

Any other information on results incl. tables

Observations remained within normal limits throughout the test interval.

Applicant's summary and conclusion

Conclusions:

Based on an absence of responses in a repeat insult patch test conducted in 208 human volunteers, dibutyl terephthalate is not classified for “Skin Sensitization” or "Skin irritation/corrosion" according to GHS guidelines.

Executive summary:

In a human repeat insult patch test using 208 volunteers, the test material was repeatedly applied under occluded contact to the upper back between the scapulae for a total of 9 applications. Each application remained in place for twenty-four (24) hours. Scoring of each patch area was made just prior to re-application. Rest periods consisted of 24 or 48 hours following patch removal. Approximately two (2) weeks after the final induction patch application, a challenge patch was applied to a virgin test site adjacent to the original induction patch site, following the same procedure described for induction. The challenge site was scored following patch removal at 24 and 72 hours post-application. Except for a moderate response in a single individual on a single occasion and a slight reaction after another induction, there was no evidence of dermal irritation or allergic contact sensitization in this study.