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EC number: 219-417-6
CAS number: 2432-99-7
For acute effects, no significant effects that would justify DNEL
derivation were observed in the corresponding toxicity studies.
1. Long term exposure-systemic toxicity
1.1 Inhalation DNEL(workers)
Occupational exposure to 11 -aminoundecanoic acid may occur
mainly by inhalation of particles, therefore we consider the inhalation
route as the most relevant for DNEL derivation.
Of all repeated dose toxicity studies in rats, the OECD TG 421
(reproductive/developmental screening) study (CIT, 2008) is selected for
DNEL derivation as it is the study where the lowest NOAEL was observed
among the repeated dose toxicity studies data set with
11-aminoundecanoic acid, and because effects on kidneys, considered as
the critical effect with a threshold mode of action, were also observed
in this study.
*NOAEL (parental toxicity) = 1250 ppm, equivalent to79
*No reproductive effects but renal effects were observed in the
parents (histopathological findings).
*Conversion into an inhalatory rat NOAEC by dividing by 0.38 m3/kg
(8-hour respiratory volume in the rat)
*No correction for inhalatory and oral absorption rates
(considered to be 100 % because 11-aminoundecanoic acid is well absorbed
by both routes)
*Correction for activity driven differences in respiratory volume
in workers compared to individuals at rest (6.7 m3/10 m3)
dose descriptor:NOAEC (worker, 8 h)= 79 x 1/0.38 x 6.7/10 = 139
*Interspecies : no allometric scaling factor is applied because an
oral-to-inhalation route extrapolation is performed. However, a factor
of 2.5 to correct for differences other than differences in
metabolic rate is applied.
*Intraspecies : the default assessment factor of 5 is
* Differences in exposure duration: as the exposure in rats was 54
days, a factor of 6 for subacute-to-chronic extrapolation is
*Dose-response relationship: a factor of 1 is applied due
to the use of a NOAEL as dose descriptor and the low toxicity of the
*Quality of whole database: a factor of 1 is applied based
on the good quality of the whole database.
*Global assessment factor: 2.5 x 5 x 6 x 1 x 1 = 75
Worker DNEL (long term, systemic effects)= 79 x
1/0.38 x 6.7/10 x 1/75 = 1.86 mg/m3
2. Dermal DNEL (workers)
Occupational exposure to 11 -aminoundecanoic acid may also occur
by dermal exposure. Although no dermal repeated dose toxicity studies is
available as well as no information on dermal absorption, we derived a
dermal DNEL based on the Oral NOAEL selected for the derivation of the
1) Relevant dose-descriptor
NOAEL, rats= (parental toxicity) =1250 ppm,
equivalent to79 mg/kg/day
of starting point:
Correction for oral to dermal absorption :
11 -aminoundecanoic acid has a low octanol partition coefficient
(log Kow=0.16) which predicts a low dermal absorption. However as no
dermal penetration study is available we consider 100% absorbsion as a
worst case (=1).
difference in dermal absorption is expected between rats and humans, no
correction factor will be applied.
3) Assessment factors
Interspecies: 2.5 x 4
Intraspecies : 5
Exposure duration : 6 (as the exposure in rats was
54 days, a factor of 6 for subacute-to-chronic extrapolation is
Quality of database:1
on NOAEL 28-d/rabbits :
x 1 x 1/(2.5 x 4 x 5 x 6 x 1 x 1) = 0.26 mg/kg bw
exposure to 11 -aminoundecanoic acid is the most relevant potential
safety concern under the conditions of use of the substance. There is no
direct consumer use of 11 -aminoundecanoic acid, Food contact materials
made of polyamide 11 contain low residual levels of 11-aminoundecanoic
acid (<100 ppm) and are subject to very strict regulations, therefore no
DNEL derivation for general population was deemed necessary.
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