Dimethyl(propyl)amine

Dermal absorption

Administrative data

Endpoint:

dermal absorption in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Data source

Reference

Reference Type:

publication

Title:

Skin absorption of the industrial catalyst dimethylethylamine in vitro in guinea pig and human skin, and of gaseous dimethylethylamine in human volunteers

Author:

Lundh T, Bowan A, Akesson B

Year:

1997

Bibliographic source:

Int Arch Occup Environ Health 70: 309-313

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Skin absorption of dimethylethylamine in vitro was determined with human skin samples.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Ethyldimethylamine

EC Number:

209-940-8

EC Name:

Ethyldimethylamine

Cas Number:

598-56-1

Molecular formula:

C4H11N

IUPAC Name:

N,N-dimethylethanamine

Radiolabelling:

no

Test animals

Species:

human

Strain:

other: Caucasian

Sex:

male/female

Details on test animals or test system and environmental conditions:

Human split-thickness skin (250 µm) was obtained at surgery from three Caucasian adults (two women aged 30 and 38 years, and one man of unknown age) and stored at 4 °C in sterile compresses wetted with isotonic saline solution less than 24 h prior to use. 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 hour.

Administration / exposure

Type of coverage:

open

Vehicle:

other: water or isotonic saline solution

Doses:

100 µL of 1% solution (0.67mg/mL)

No. of animals per group:

not applicable

Control animals:

no

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 and 100 µL of the solution were applied to the skin surface.
The perfusion medium, Hanks balanced salt solution was supplied at a flow rate of 1.5 mL/hour using a peristaltic pump (Alitea, Stockholm. Sweden) to ensure skin conditions. Using a fraction collector (Gilson 202, France) the perfusion fluid was collected at 2h-intervals for 48 h in vials containing 100 µL of 1 M hydrochloric acid (HCl 37% Merck, Darmstadt, Germany). The 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).

Remark:
The uptake of DMEA in the in vivo experiments and the DMEA content in the perfusion fluid collected in the in vitro experiments were expressed as the combined amount of DMEA and DMEAO (E-DMEA).Day-to-day variations (relative standard deviations) based on nine analyses of spiked perfusion fluid specimens containing 0.51 µg/mL DMEA was 5.1%. The corresponding value for urine analyses with a concentration of 0.047 µg/ml was 8.1%.

Results and discussion

Absorption in different matrices:

DMEA penetrated human skin. The median Jss and Kp were 0.017 mg/cm² x h and 0.003 cm/h, respectively, for split-thickness human skin. No DMEAO could be found in the perfusion medium.

Percutaneous absorption

Key result

Dose:

1%

Parameter:

other: permeability coefficient (Kp)

Remarks on result:

other: 0.003cm/h for human 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
Human skin	1	0.026	(0.018 0.029)	0.004	(0.003-).004)	Neg
	2	0.011	(0.007-0.026)	0.002	(0.001-0.004)	Neg
	3 a	0.016	(0.011-0.019)	0.002	(0.002-0.003)	1	(1-4)
a DMEA diluted with isotonic saline solution
b Negative, the curve shape did not allow lag-time calculation