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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:
key study
Study period:
1982
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study meets generally accepted scientific principles.

Data source

Reference
Reference Type:
publication
Title:
Percutaneous Absorption of Organic Solvents III. On the Penetration Rates of Hydrophobic Solvents through the Excised Rat Skin
Author:
TSURUTA, Hiroshi
Year:
1982
Bibliographic source:
Industrial Health, 1982, 20, 335-345.

Materials and methods

Test guideline
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 428 (Skin Absorption: In Vitro Method)
Principles of method if other than guideline:
Penetration rates of 10 hydrophobic solvents through the excised abdominal rat skin were quantitatively determined
GLP compliance:
no

Test material

Constituent 1
Reference substance name:
n-heptane
IUPAC Name:
n-heptane

Administration / exposure

Type of coverage:
other: chamber
Vehicle:
unchanged (no vehicle)
Duration of exposure:
4, 5, 6, 10, 13, 16, 20 hours
Doses:
N/A
No. of animals per group:
N/A
Control animals:
no
Remarks:
N/A
Details on study design:
see below
Details on in vitro test system (if applicable):
Materials
The solvents were examined for purity by a gas chromatograph with a flame ionization detector. The purity of the solvents was more than 98%.

Excised skin
The rats (SD-JCL), weighing 400 to 600 g, were anesthetized by a subcutaneous injection of 0.60 to 0.90 ml of sodium pentobarbital solution. The skin of the abdominal wegion was clipped with an electric clipper and then completely de- pilated with, a depilatory cream. After three days of depilating the hair of the abdominal skin, the rat was sacrificed with carbon monoxide gas, and the abdominal skin freed of subcutaneous tissue was stripped with scissors. The skin obtained was spread on aluminium foil and stored at 20°C. Before use, the skin was allowed to adjust itself gradually to room temperature.

Operation of the in vitro experiment by the diffusion cell
The area of the skin attached to the diffusion cell was 2.55 cm2. The lower chamber was filled with 0.9% NaCI solution. After 1 ml of test solvent was added to the upper chamber with a glass stopper, the diffusion cell was reciprocally shaken at 25 deg C. After a certain number of hours of shaking, the 0.9% NaCl solution in the lower chamber was throughly removed, and amount of the test solvent that had penetrated into the 0.9% NaC1 solution was determined.


Analysis of the solvents by gas chromatography
A Shimadzu GC-4BM gas chromatograph with a gas sampling valve of a 2-mL gas sampler attached to it was used in this study. The carrier gas was nitrogen. The chromatograph column was a 0.5-rn glass tube (ID. 3 mm, O.D. 5 umm) packed with Porapak OS, 60-80 mesh. The column temperature was 190 deg C for n-heptane.

Data
A plot of the log of the solvent concentration in the gas phase versus the number of equilibrations produces a straight line. The rate of penetration was determined by measuring the accumulation of the test solvent in the 0.9% NaCl solution beneath the skin.

Results and discussion

Signs and symptoms of toxicity:
not specified
Dermal irritation:
not specified
Percutaneous absorption
Dose:
N/A
Remarks on result:
other: overall absorption rate
Remarks:
0.0241 nmol/min/cm2 of skin

Applicant's summary and conclusion

Conclusions:
The percutaneous absorption rate for n-heptane was determined to be 0.0241 nmol/min/cm2.
Executive summary:

The percutaneous absorption rate for n-heptane was determined to be 0.0241 nmol/min/cm2.