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Toxicological information

Dermal absorption

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Administrative data

Endpoint:
dermal absorption in vitro / ex vivo
Type of information:
experimental study
Adequacy of study:
other information
Study period:
1984
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study without detailed documentation

Data source

Reference
Reference Type:
publication
Title:
Absorption of some glycol ethers through human skin in vitro
Author:
Dugard PH, Walker M, Mawdsley SJ, Scott RC
Year:
1984
Bibliographic source:
Env Hlth Persp, 57, 193-7

Materials and methods

Test guideline
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 428 (Skin Absorption: In Vitro Method)
Principles of method if other than guideline:
The study seems to follow main requirements of the OECD protocol although not all information is included in publication to judge if it is followed exactly. The test substance was not radiolabelled therefore there was no attempt at a mass balance. Not enough raw data reported to meet protocol requirements. Some minor detail of experimental methods also lacking.
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): 2-(2-butoxyethoxy)ethanol, diethylene glycol monobutyl ether, DB
- Physical state: liquid
- Analytical purity: >98%
- Other: Source: ICI Petrochemicals and Plastics division, Wilton, UK
Radiolabelling:
no

Test animals

Species:
human
Strain:
other: not applicable
Sex:
not specified
Details on test animals and environmental conditions:
no further data on source of skin.

Administration / exposure

Type of coverage:
other: not aplicable as study in vitro
Vehicle:
unchanged (no vehicle)
Duration of exposure:
8 hours
Doses:
Single
No. of animals per group:
not applicable
Control animals:
no
Details on study design:
See other information below.
Details on in vitro test system (if applicable):
SKIN PREPARATION
- Source of skin: Obtained post mortem, source unknown.
- Ethical approval if human skin: no data
- Type of skin: Abdominal whole skin
- Preparative technique: Subcutaneous fat removed, then immersed in water (60C, 45 seconds) to allow separation of epidermis. Discs then cut for diffusion cells (1.8cm2 absorption area).
- Membrane integrity check: By following time dependent diffusion of tritiated water before and after exposure to the substance. Skin samples showing a tritiated water permeability greater than 0.0015cm/hr over 6 hours were rejected.

PRINCIPLES OF ASSAY
- Solubility of test substance in receptor fluid: complete
- Static system: Yes
- Test temperature: 30C

Results and discussion

Signs and symptoms of toxicity:
not specified
Remarks:
not applicable
Dermal irritation:
not specified
Remarks:
not applicable
Absorption in different matrices:
not applicable
Total recovery:
not applicable
Conversion factor human vs. animal skin:
no data

Any other information on results incl. tables

Steady state was achieved during the experiment; maximum rate was achieved after 5 hours. At 2.5hours the adsorption rate was less than that of the 5 hour rate, generally showing a 2 hour lag time. The permeability constant was calculated at 0.0000357cm/hr with a rate of absorption of 0.035 +/-0.025mg/cm2/hr, based on 9 determinations. The damage ratio (ratio of tritiated water permeability before and after exposure) was 2.05+/-1.01 (5 determinations) which is within the 1-2 figure for controls leading to the conclusion that 2-(2-butoxyethoxy)ethanol dose not have any significant irreversible effects on skin barrier function.

Applicant's summary and conclusion

Conclusions:
skin uptake is unlikely to be a significant route of exposure
Executive summary:

An in vitro dermal absorption study using human skin showed that 2 -(2 -butoxyethoxy)ethanol is able to pass through the stratum corneum but only at a slow rate (35ug/cm2/hr) and does so without causing any significant detectable damage to the skin. There is a lag time of approximately 2 hours for substance to cross the skin and appear in the receptor fluid