Benzene

Direct observations: clinical cases, poisoning incidents and other

Administrative data

Endpoint:

direct observations: clinical cases, poisoning incidents and other

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Non-GLP, non-guideline human experimental study, published in peer reviewed literature, limitations in design but otherwise adequate for assessment

Data source

Reference

Reference Type:

publication

Title:

In vivo percutaneous absorption of benzene in man: Forearm and palm

Author:

Modjtahedi, B.S. and Maibach, H.I.

Year:

2008

Bibliographic source:

Food Chem. Toxicol., 46, 1171-1174

Materials and methods

Study type:

study with volunteers

Endpoint addressed:

dermal absorption

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

The percutaneous absorption of [14C]-benzene was determined by measuring excretion of radioactivity.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Benzene

EC Number:

200-753-7

EC Name:

Benzene

Cas Number:

71-43-2

Molecular formula:

C6H6

IUPAC Name:

benzene

Details on test material:

Radiolabelled - 14C
Benzene (purity, 100%) was supplied by ARC, St. Louis, Missouri.

Method

Type of population:

general

Subjects:

- Number of subjects exposed: 8 (4 per route)
- Sex: Male
- Age: Adult

Ethical approval:

confirmed, but no further information available

Route of exposure:

dermal

Details on exposure:

Adult male volunteers were exposed dermally, the dose was applied while the exposed limb was inside a fume hood with the partition down. Volunteers wore a respirator during application to the forearm and until the dose had evaporated, no respiratory protection was used during palmar exposure.

Examinations:

Palmar exposure: Pooled urine samples were collected at 4, 8, 12 and 24h and then daily up to 7 days after dosing.
Forearm exposure: Pooled urine samples were collected at 4, 8, 12 and 24h and then daily up to 7 days after dosing; Stool samples were also collected.
Samples were analysed for radioactivity, values were corrected for incomplete collection.

Results and discussion

Results of examinations:

Percutaneous absorption from a 100uL applied dose was approx. 0.1%

Any other information on results incl. tables

Total recovery

48 and 42% of the recovered radioactivity was excreted within 24h following palm and forearm exposure respectively. Radioactivity in stool samples was below the limit of detection.
0.13±0.04% of the palmar dose was absorbed, the corresponding value for forearm exposure was 0.07±0.04%; there was no statistically significant difference between the results for palm and forearm.

Applicant's summary and conclusion

Conclusions:

Percutaneous absorption of benzene through human fore-arm and palm skin is low. Total absorption was approximately 0.1 % (0.07% for forearm and 0.13% for palm).

Executive summary:

Absorption of benzene through human skin in vivo was investigated in 2 groups of 4 male volunteers following one topical application to the forearm or palm. A dose of 100uL of benzene/¹⁴C benzene was applied under controlled conditions. Urine and stool samples were collected for a total of 6 or 7 days and analysed for radioactivity. Absorption values were found to be nominal with forearm exposure showing an average total absorption of 0.07±0.04% and palmar exposure an average total absorption of 0.13±0.04% of the applied dose.