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Dermal absorption

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dermal absorption in vitro / ex vivo
Type of information:
migrated information: read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Test procedure in accordance with national standard methods with acceptable restrictions

Data source

Reference Type:
Skin absorption of the industrial catalyst dimethylethylamine in vitro in guinea pig and human skin, and of gaseous dimethylethylamine in human volunteers
Lundh T, Bowan A, Akesson B
Bibliographic source:
Int. arch Occup Environ Health 70, 309-313

Materials and methods

Test guideline
no guideline followed
Principles of method if other than guideline:
Skin absorption of dimethylethylamine in vitro was determined with human and guinea pig skin samples.
GLP compliance:
not specified

Test material

Constituent 1
Chemical structure
Reference substance name:
EC Number:
EC Name:
Cas Number:
Molecular formula:
Details on test material:
- Name of test material (as cited in study report): dimethylethylamine
- Purity: 99%
- Source: Janssen Chemical. Geel. Belgium

Test animals

guinea pig
other: albino
Details on test animals or test system and environmental conditions:
Fresh full-thickness albino guinea-pig skin was used (mean 640 g, obtained from Sahlin's Forsoksdjursfarm, Malmo, Sweden). The skin was mounted in Teflon flow-through cells (Vangard International, Neptune, N.J.; Bronaugh 1991). Before exposure, the skin was left to acclimatize for 1 h.

Administration / exposure

Type of coverage:
other: water or isotonic saline solution
100 µl of 1% solution (0.67mg/ml)
Control animals:
Details on in vitro test system (if applicable):
DMEA was diluted to 1% (i.e. 0.67 mg/ml) with water or isotonic saline solution, 100 µl of the solution being applied to the skin surface.
The perfusion medium, Hanks balanced salt solution was supplied at a flow rate of 1.5 ml/h using a peristaltic pump (Alitea, Stockholm. Sweden) to ensure sink conditions.
Using a fraction collector (Gilson 202. France). the perfusion fluid was collected at 2h-intervals for 48 h in vials containing 100 µl 1 M hydrochloric acid (HCl 37% Merck, Darmstadt, Germany).
Steady-state flux (Jss) was calculated from the slope of the linear portion of the plot of cumulative amount penetrated /cm² versus time for each cell. The permeability coefficient (Kp) at apparent steady state or at the peak absorption rate was calculated according to Fick's law as: Kp =Jss/C where Kp is the permeability coefficient (cm/ h), Jss the steady-state flux (mg/cm² x h) and C the concentration of penetrating chemical in the medium (mg/cm²).

Results and discussion

Signs and symptoms of toxicity:
not examined
Dermal irritation:
not examined
Absorption in different matrices:
DMEA penetrated guinea pig skin.
The median Jss and Kp were 0.009 mg/cm2 x h and 0.001 cm/h, respectively.
No DMEAO could be found in the perfusion medium.
Percutaneous absorption
Remarks on result:
other: Kp= 0.001cm/h for guinea pig skin

Any other information on results incl. tables

The steady-state flux permeability coefficient (Kp) and the lag-time obtained in the in vitro experiments.
The respective medians from each experiment are based on data obtained from six flow-through cells
  Experiment n° Jss (mg/cm² x h) Kp (cm/h) Lag-time (h)
Mean Range Mean Range Mean Range
Guinea-pig skin 1 0.008 (0.008-0.011) 0.001 (0.001-0.002) 7 (3 9)
2 0.005 (0.004-0.009) 0.001 (0.001-0.001) Neg b  
3 a 0.025 (0.018-0.027) 0.004 (0.002-0.004) 3 11-5)
4 a 0.009 (0.006-0.023) 0.002 (0.001-0.003) 8 (6-10)
a DMEA diluted with isotonic saline solution
b Negative, the curve shape did not allow lag-time calculation

Applicant's summary and conclusion

Executive summary:

The aims of the study was to assess the skin uptake of dimethylethylamine (DMEA) in vitro from water solutions by fresh guinea-pig specimens. Specimens were analysed by gas chromatography using a nitrogen-sensitive detector. DMEA, diluted with water or isotonic saline solution was applied to fresh guinea-pig skin, mounted in Teflon flow-through cells with a perfusion fluid flow rate of 1.5 ml/h, samples being collected at 2-h intervals for 48 h. DMEA penetrated guinea-pig . The median steady-state flux and permeability coefficient (Kp) values, were 0.009 mg/cm2 x h and 0.001 cm/h, respectively.