Benzoic acid

Sensitisation data (human)

Administrative data

Endpoint:

sensitisation data (humans)

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

other: test to assess the influence of irradiation on skin reactions

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1989

Materials and methods

Type of sensitisation studied:

skin

Study type:

study with volunteers

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Effect of infra-red A (IRA) (600-2000 nm) and 1064 nm laser irradiation on non-immunologic contact reactions (NIICRs) induced by the test substance were studied. Five concentrations of the test substance were tested, on two subsequent days, without occlusion on the upper arm of 10 or 12 test subjects, with a dose of IRA irradiation that elevated surface temperature of the skin to 39.5 ℃. In the first group exposed to IRA irradiation, the NIICR tests were performed immediately after the surface temperature of the skin had reached 39.5 ℃ was attained, and the skin temperature was kept unchanged another 15 min. In the 1064 nm laser exposure group of 12 subjects, the tests were performed on the upper back immediately after irradiation of the skin with 100, 50 and 25 J/cm2 of 1064 nm laser. Reactions were monitored with laser-Doppler flowmeter 20 and 40 min after application, and erythema and edema were graded visually.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Benzoic acid

EC Number:

200-618-2

EC Name:

Benzoic acid

Cas Number:

65-85-0

Molecular formula:

C7H6O2

IUPAC Name:

benzoic acid

Details on test material:

No data given

Method

Type of population:

general

Ethical approval:

confirmed and informed consent free of coercion received

Subjects:

- Number of subjects exposed: The first group comprised 10 volunteers, the second 12 volunteers.- Sex: the first group: 4 females, 6 males; the second group: 6 females, 6 males- Age: The first group: mean age 33 years; the second group: mean age 34 yearsNo additional data

Clinical history:

- Symptoms, onset and progress of the disease: The first group comprised 2 atopies, the second group contained 3 atopies.- Other: The volunteers received no anti-inflammatory analgesics or antihistaminic drugs for three days before the tests and none during them.No additional data

Controls:

Petrolatum was used as control.

Route of administration:

dermal

Details on study design:

TYPE OF TEST(S) USED: patch test (epicutaneous test) ADMINISTRATION- Type of application: open- Vehicle / solvent: petrolatum- Concentrations: 250, 125, 62 and 31 mM- Volume applied: 10 μL- Testing/scoring schedule: Erythema and edema reactions were graded visually 20 and 40 min after application.- Removal of test substance: Test substance in all three groups was wiped away with blotting paper 15 min after application.- Other: The test substance and the control were applied 2 cm apart, without occlusion, on a 1×1 cm area on the outer aspects of both upper arms in both groups. Each concentration of the test substance was applied to skin on the upper back irradiated with 100 J/cm2 of 1064 nm laser, and 125 mM the test substance and 5 mM and petrolatum as a reference were applied to the areas irradiated with 50 and 25 J/cm2 of 1064 laser. The test subjects were sitting in a room with a temperature of 26 ± 2 ℃.EXAMINATIONS- Grading/Scoring system: -, no reactions; +, faint; ++, moderate; +++, strong - Statistical analysis: Student’s t-test for paired observations was used for the results of LDF measurements, and the wilcoxon signed rank test for paired observations for visual observations of NIICRs.- Other: The blood flow was measured using a laser-Doppler (LDF). The results were expressed as percentages of the blood flow values at the test sites compared with values at the reference sites.No additional data

Results and discussion

Results of examinations:

In group 1, IRA radiation didn’t enhance the reaction to the test substance. Visually, there were no differences between the reactions at irradiated and non-irradiated test sites.In group 2 on the first day, reactions to all concentrations of the test substance were enhanced at test sites irradiated with IRA, both in LDF measurement and in visual observation (two highest concentrations (p<0.05)).Blood flow in the reactions to 250, 125 and 62 mM the test substance at the test sites irradiated with 100 J/cm2 of 1064 nm laser was increased on the first day and to a lesser extent on the following day. Visually, there were no differences in the erythema or edema of NIICRs between exposed and non-exposed test areas.

Applicant's summary and conclusion

Conclusions:

In the first group exposed to IRA, the warming had no enhancing effect on the test substance. In the second group exposed to IRA irradiation, the NIICRs occurring form the test substance on the exposure day were stronger on the exposed than both the reactions on the non-exposed area. 1064 nm laser irradiation enhanced the NIICRs induced by the test substance on both the exposure day and on the following day.

Executive summary:

Effect of infra-red A (IRA) (600-2000 nm) and 1064 nm laser irradiation on non-immunologic contact reactions (NIICRs) induced by the test substance were studied. Five concentrations of the test substance were tested, on two subsequent days, without occlusion on the upper arm of 10 or 12 test subjects, with a dose of IRA irradiation that elevated surface temperature of the skin to 39.5 ℃. In the first group exposed to IRA irradiation, the NIICR tests were performed immediately after the surface temperature of the skin had reached 39.5 ℃ was attained, and the skin temperature was kept unchanged another 15 min. In the 1064 nm laser exposure group of 12 subjects, the tests were performed on the upper back immediately after irradiation of the skin with 100, 50 and 25 J/cm2 of 1064 nm laser. Reactions were monitored with laser-Doppler flowmeter 20 and 40 min after application, and erythema and edema were graded visually.

 

In the first group exposed to IRA, the warming had no enhancing effect on the test substance. In the second group exposed to IRA irradiation, the NIICRs occurring form the test substance on the exposure day were stronger on the exposed than both the reactions on the non-exposed area. 1064 nm laser irradiation enhanced the NIICRs induced by the test substance on both the exposure day and on the following day.