Amines, N-C10-16-alkyltrimethylenedi-, reaction products with chloroacetic acid

Endpoint summary

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

basic toxicokinetics in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Objective of study:

metabolism

toxicokinetics

Qualifier:

according to guideline

Guideline:

OECD Guideline 417 (Toxicokinetics)

Version / remarks:

1984

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.36 (Toxicokinetics)

Version / remarks:

1988

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Radiolabelling:

yes

Species:

rat

Strain:

other: CD / Crl:CD(SD)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Ltd., Sulzfeld, Germany
- Age at study initiation: 7 weeks (males), 9-12 weeks (females)
- Weight at study initiation: 228–252 g (males), 210–288 g (females)
- Fasting period before study: no
- Housing: individually
- Individual metabolism cages: no
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 5-8 d

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22±3
- Humidity (%): 55±15
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

other: Oral - gavage (single administration: Group 1, 2 and 3; repeated administration: group 5); intravenous (single administration: group 4)

Vehicle:

other: Oral (group 1, 2, 3 und 5): 0.8 % aqueous hydroxypropyl-ethyl-cellulose gel; Intravenous (group 4): 0.9 % NaCl solution

Duration and frequency of treatment / exposure:

single oral administration: Group 1, 2 and 3
repeated oral administration: group 5; once daily for 13 d
single intravenous administration: group 4

Dose / conc.:

30 mg/kg bw/day

Remarks:

each dose contained 0.49 mg 14C-labelled test item/kg bw corresponding to a radioactive dose of 700 kBq/kg bw.

Dose / conc.:

100 mg/kg bw/day

Remarks:

each dose contained 0.49 mg 14C-labelled test item/kg bw corresponding to a radioactive dose of 700 kBq/kg bw.

No. of animals per sex per dose / concentration:

Group 1 (low dose): 8 females
Group 2 (low dose): 4 males and 4 females
Group 3 (high dose): 4 males and 4 females
Group 4 (low dose): 8 females
Group 5 (repeated low dose): 4 females

Control animals:

no

Details on study design:

Pilot study:
In order to determine the high dose level for the main study an orientating acute oral toxicity test and a preliminary excretion experiment to determine the relevance of excretion via expired air were carried out. Based on the results of these preliminary studies the following decisions were made for main study:
A high dose level of 100 mg/kg bw was used in the main study;
Excretion of test substance via expired air was significant and thus measured during main study.

Statistics:

Pharmacokinetic evaluation of plasma data using program TopFit 2.11

Preliminary studies:

The following no-effects levels were determined in an orientating experiment:
NOEL rat, i.v. = 125 mg/kg bw; NOEL rat, p.o = 400 mg/kg bw.
The administered radioactivity was distributed as follows: Approximately 55 %/19 % (p.o./i.v.) in the faeces, 6 %/23 % in urine, 0.6 %/0.9 % in cage wash, and 12 % (p.o.) in expired air. The mean of the highest plasma concentration was 0.04 %/0.25 % (p.o./i.v.). The fraction of radioactivity excreted in expired air indicated that this route of elimination is relevant.

Type:

absorption

Results:

34% oral absorption

Type:

distribution

Results:

throughout the body, with the highest levels in the residual carcass, in the liver, the kidneys, and the adipose tissue

Type:

metabolism

Results:

mainly oxidation (hydroxylation), to a minor extent dehydrogenation and acetylation

Type:

excretion

Results:

excreted rapidly within 24 hours; main elimination pathway: via the faeces, followed by expired air and urine

Details on absorption:

Oral absorption: The systemic bioavailability of 14C labelled test substance was 34 % following oral administration, as derived from the comparison of the AUC0–∞ (see Table A6.2- 2).

Details on distribution in tissues:

Radioactivity was distributed throughout the body, with the highest levels in the residual carcass, in the liver, the kidneys, and the adipose tissue. Nevertheless, distribution was quite uniform across all examined organs with no tissue storage in brain, heart, ovaries and spinal cord. There was no significant difference in the distribution of radioactivity in the tissues after single or repeated administration of 30 mg test substance/kg bw.
Results of tissue distribution are summarised in the Table A6.2- 3.

Details on excretion:

The vast majority of the administered radioactivity was excreted rapidly within 24 hours.
The main elimination pathway was via the faeces, followed by expired air and urine in all test groups. See Table A6.2- 1 for details.
After 168 hours approximately 60% of the radioactivity administered had been excreted via the faeces in the male and female animals, approximately 18% was excreted via expired air (approx. 15% in the males, 20% in the females), and approximately 9% was recovered in the urine. Less than 20% was found in organs and carcass.
There were no relevant differences in the mean radioactive recovery after 24 or 168 hours from urine and cage wash between the low, high, and repeated dose groups (see Table A6.2- 1).

Metabolites identified:

yes

Details on metabolites:

In urine, the parent compounds N-C12 Gly, N’-C12 Gly, N’-C12 di Gly, C12 PDA and several metabolites were identified by mass spectrometry. Oxidation (hydroxylation) of the parent and some other metabolites like dehydrogenated and acetylated compounds, especially for C12 PDA, were identified. The most abundant compounds in urine were the oxidation products.
In plasma, only the unchanged parent compounds N-C12 Gly, N’-C12 Gly, N’-C12 di Gly, C12 PDA could be identified by mass spectrometry. For the radioactivity counting only N-C12 Gly, N’-C12 Gly were identified. The most abundant compounds in plasma were the parent substance N-C12 Gly and N’-C12 Gly.
In faeces, N-C12 Gly, N’-C12 Gly, N’-C12 di Gly, C12 PDA and several metabolites were identified by mass spectrometry. Oxidation (hydroxylation) of the parent and some other metabolites, like dehydrogenated and acetylated modifications, was demonstrated. The most abundant compounds in faeces were the oxidation products.

 

Toxic effects, clinical signs	In the main experiment one male animal died prematurely and was found dead on test day 6. This death was not test item-related, but caused by a congested and blocked absorber for CO2determination. The faeces of all rats showed a normal consistency during the entire experimental period. No other effects were reported.
Recovery of labelled compound	Total recovery of administered radioactivity as determined in the excretion studies ranged from 97 to 103 % (rounded, seeTable A6.2-1).
Pharmacokinetics	After administration of 30 mg/kg bw (low dose) of [^14C]-labeled test substancevia the oral and intravenous route the following toxicokinetic parameters were established: Plasma half-life: approx. 74 h both in the p.o. and i.v. group

 

 

 Table A6.2-1:Excretion: Mean recovery of radioactivity (%) after administration of [¹⁴C]-labelled test substance

	Group 2: Single low dose 30 mg/kg bw		Group 3: Single high dose 100 mg/kg bw		Group 5: Repeated low dose 30 mg/kg bw
	Male	Female	Male	Female	Female
Number of animals	4	4	4	4	4
Urine (0–24 h)	6.88 ± 0.56	6.65 ± 0.42	7.92 ± 0.66	7.77 ± 0.72	6.62 ± 0.88
Urine (0–168 h)	8.59 ± 2.52	8.39 ± 2.42	9.84 ± 2.90	10.03 ± 2.83	8.92 ± 2.39
Faeces (0–24 h)	51.06 ± 3.26	51.72 ± 3.28	49.03 ± 2.82	44.01 ± 3.89	42.35 ± 4.04
Faeces (0–168 h)	59.32 ± 19.16	59.47 ± 18.89	58.55 ± 18.13	57.68 ± 16.24	54.17 ± 15.55
Expired air (0–24 h)	10.13 ± 2.72	12.74 ± 0.77	9.85 ± 1.20	13.00 ± 2.21	7.84 ± 1.42
Expired air (0–168 h)	15.39 ± 3.58	21.49 ± 4.44	15.57 ± 3.46	21.53 ± 4.53	13.76 ± 2.68
Cage wash (0–168 h)	0.31 ± 0.08	0.28 ± 0.06	0.15 ± 0.03	0.34 ± 0.07	0.40 ± 0.06
Carcass and organs	n.e.	13.33* ± 4.24*	n.e.	n.e.	19.22 ± 6.20
Total		102.96			96.47
Data expressed as mean % of total dose (dpm) administered ± standard deviation *          Values derived from test group 1 with 8 female test animals administered orally a single low dose of test substance n.e.:    not examined

 

 

Table A6.2-2:Toxicokinetic parameters for [¹⁴C]-labelled test substance.

Dosage	Route of administration	Noncompartmental analysis
		Cmax^# [Bq/mL]	tmax^# [h]	t1/2 [h]	AUC0-120 h [Bq*h/mL]	AUC0-¥h [Bq*h/mL]	AUC/dose^##[g*h/mL]
30 mg/kg bw	p.o.	47.5	6.00	76.62	2733.30	4126.83	6.87
	i.v.	606.5	-	71.28	9304.88	12121.16	16.76
#         Values obtained from the analytical results, all other values calculated by toxicokinetic analysis ##       Dose in Bq/kg b.w. (mean values per group) i.v.      intravenous administration p.o.     oral administration

 

Table A6.2-3:Distribution:Mean recovery of radioactivity (%) in organs at termination

	Group 1: Single oral dose 30 mg/kg bw	Group 4: Single intravenous dose 30 mg/kg bw	Group 5: Repeated oral dose 30 mg/kg bw
	Female	Female	Female
Number of animals	8	8	4
Adipose tissue	0.07 ± 0.01	0.11 ± 0.05	0.15 ± 0.06
Brain	0.02 ± 0.00	0.07 ± 0.01	0.02 ± 0.01
Carcass	12.13 ± 3.94	19.06 ± 2.16	17.72 ± 2.72
Heart	0.02 ± 0.01	0.09 ± 0.02	0.03 ± 0.01
Kidneys	0.17 ± 0.03	0.75 ± 0.19	0.22 ± 0.04
Liver	0.91 ± 0.21	3.72 ± 0.68	1.06 ± 0.50
Ovaries	0.01 ± 0.01	0.05 ± 0.01	0.02 ± 0.01
Spinal cord	0.00 ± 0.00	0.01 ± 0.00	0.00 ± 0.00
Total	13.33 ± 4.24	23.86 ± 6.62	19.22 ± 6.20
Data expressed as mean % of total dose (dpm) administered ± standard deviation

 

Figure A6.2-1:Proposed pathway of the metabolism of N-C12 Gly

see attached Image file

Conclusions:

Interpretation of results: low bioaccumulation potential based on study results
The systemic bioavailability of 14C labelled registration substance was 34% following oral administration.
The substance was distributed throughout the body, with the highest levels in the residual carcass, in the liver, the kidneys, and the adipose tissue.
The plasma half-life was determined to be approx. 74 h.
The substance is mainly metabolised by oxidation (hydroxylation), and to a minor extent dehydrogenation and acetylation.
The vast majority of the administered radioactivity was excreted rapidly within 24 hours. The main elimination pathway was via the faeces, followed by expired air and urine.

Executive summary:

Absorption, distribution, metabolism and excretion of [¹⁴C]- registration substance (20% a.i.) were investigated in the rat according to the OECD test guideline 417. The test substance was administered orally by gavage at two single dose levels of 30 and 100 mg/kg bw, singly intravenous and orally at one repeated low dose level.

Upon oral administration, radioacitivity was predominantly eliminated via faeces (approx. 60 %) and via expired air (approx. 18 %). A lower proportion was excreted via urine (approx. 9 %) and less than 20 % of the administered dose was found in the carcass. No significant differences of absorption and elimination of test substance regarding high or low dose, repeated administration or sex could be indentified. The recovery of radioactivity was greatest in the residual carcass (12–19 %), followed by the liver (approx 4 %). In all other tissues the radioactive recovery was low (≤ 1.00 %) and quite uniformly distributed, with no tissue storage in brain, heart, ovaries and spinal cord. There was no relevant difference in the tissue distribution of radioactivity between animals treated orally or intravenously with a single or repeated dose of the test substance. The elimination half-life was approx. 74 hours both in the p.o. and i.v. group.

The systemic bioavailability, assessed by comparison of plasma radioactivity after oral and intravenous administration, was 34%.

In plasma, only parent substances but no transformation products could be identified. A first-pass effect following intestinal absorption is therefore unlikely. In urine and faeces, parent substances as well as transformation products were detected. Metabolites in both urine and faeces were characterised by oxidation (hydroxylation) of the parent and some other metabolites like dehydrogenated and acetylated compounds. The most abundant compounds in urine were the oxidation products.

Reference 2

Endpoint:

dermal absorption in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 428 (Skin Absorption: In Vitro Method)

Version / remarks:

2004

Deviations:

no

GLP compliance:

yes

Radiolabelling:

yes

Species:

human

Sex:

female

Type of coverage:

open

Vehicle:

other: tap water

Duration of exposure:

6 hours
Termination by washing skin sample surface with commercial soap concentrate followed by rinsing with a dilute soap solution and drying with tissue swabs.

Doses:

Test preparation 1: 14C test substance (21.094 % a.i.) determined by radioactivity
Test preparation 2: 14C test substance (0.228 % a.i.) determined by radioactivity (diluted with tap water)

Details on in vitro test system (if applicable):

SKIN PREPARATION
- Skin samples: Split-thickness human skin membrane samples

APPARATUS
Automated flow-through diffusion cell apparatus (Scott/Dick, University of Newcastle-upon-Tyne, UK), placed in a steel manifold heated via a circulating water bath to maintain the skin surface temperature. The cells were connected to multi-channel peristaltic pumps from their afferent ports with the receptor fluid effluent dropping via fine bore tubing into scintillation vials on a fraction collector.

PRINCIPLES OF ASSAY
- Volume applied: 10 µL/cm²; the surface area of exposed skin within the cells was 0.64 cm².
- Receptor fluid: Tissue culture medium containing bovine serum albumin (ca 5%, w/v), glucose (ca 1%, w/v), streptomycin (0.1 mg/mL) and penicillin G (100 units/mL). The receptor chamber volume was 0.25 mL, the peristaltic pumps were adjusted to maintain a flow-rate of ca 1.5 mL/h.

Signs and symptoms of toxicity:

not examined

Remarks:

not applicable

Dermal irritation:

no effects

Total recovery:

Test preparation 1, 20 % (w/w): 101.69 % (SD = 3.04%)
Test preparation 2, 0.2 % (w/w): 97.10 % (SD = 2.99%)

Key result

Dose:

20%

Parameter:

percentage

Absorption:

1.1 %

Remarks on result:

other: 24 h

Remarks:

potentially absorbable dose (sum of the absorbed dose, exposed skin and stratum corneum tape strips 3–20)

Key result

Dose:

0.2%

Parameter:

percentage

Absorption:

15.1 %

Remarks on result:

other: 24 h

Remarks:

potentially absorbable dose (sum of the absorbed dose, exposed skin and stratum corneum tape strips 3–20)

Dose:

20%

Parameter:

percentage

Absorption:

0.6 %

Remarks on result:

other: 24 h

Remarks:

Dermal delivery (exposed skin + absorbed dose)

Dose:

0.2%

Parameter:

percentage

Absorption:

5 %

Remarks on result:

other: Dermal delivery (exposed skin + absorbed dose)

Test preparation 1, 20 % (w/w):99.76 % of the applied dose was removed by washing at 6 h post application. At 24 h post application, the total dislodgeable dose was 100.35 % of the applied dose. The stratum corneum retained 0.72 % of the applied dose, 0.37 % was removed with the first 5 tape strips.

Absorbed dose: 0.01 % (0.18 ng equivalent/cm²)

Dermal delivery: 0.62 % (13.17 ng equivalent /cm²)

Potentially absorbable dose: 0.97 % (20.53 ng equivalent /cm²)

Test preparation 2, 0.2 % (w/w): 73.66 % of the applied dose was removed by washing at 6 h post application. At 24 h post application, the total dislodgeable dose was 75.30 % of the applied dose. The stratum corneum retained 16.08 % of the applied dose, 9.71 % was removed with the first 5 tape strips.

Absorbed dose: 0.11 % (0.02 ng equivalent /cm²)

Dermal delivery: 5.04 % (1.01 ng equivalent /cm²)

Potentially absorbable dose: 11.42 % (2.28 ng equivalent /cm²)

 

 

Table A6.2-4:Details on human skin.

Donor no.	Sex/age of donor	Site of sampling	Supplier	Membrane full-thickness (µm)	Membrane split-thickness (µm)
0164	F/28Y	Breast	St. Johns Hospital	1010–1150	380–390
0161	F/36Y	Abdomen	BUPA	1020–1080	390–400
0162	F/35Y	Abdomen	BUPA	700–1190	390–400
0179	F/84Y	Breast	Nottingham	1130	400
0169	F/82Y	Breast	Nottingham	1000	400
0180	F/74Y	Breast	Nottingham	940–1000	400
0166	F/33Y	Abdomen	Transkin	1240	400

 

 

Table A6.2-5:Summary of the results (mean values).

Test preparation	1		2
Target concentration of active substance	20 % (w/w)		0.2 % (w/w)
Active substance concentration in test preparation by radioactivity	21.016 % (w/w)		0.199 % (w/w)
Application rate of Test preparation	10.06 mg/cm²		10 µl/cm²
Application rate of test item	2114 µg equivalent/cm²		19.94 µg equivalent/cm²
Distribution	% applied dose	ng equivalent /cm²	% applied dose	ng equivalent /cm²
Dislodgeable dose 6 h (skin wash+tissue swab+pipette tips)	99.76	2108.47	73.66	14.69
Total dislodgeable dose (dislodgeable dose 6 h +stratum corneum + unexposed skin + cell wash)	100.35	2120.83	75.30	15.02
Unabsorbed dose	101.07	2136.17	92.06	18.36
Absorbed dose (cumulative receptor fluid + receptor rinse)	0.01	0.18	0.11	0.02
Dermal delivery (exposed skin + absorbed dose)	0.62	13.17	5.04	1.01
Potentially absorbable dose (dermal delivery + stratum corneum tape strips)	0.97	20.53	11.42	2.28
Mass balance (unabsorbed dose + dermal delivery)	101.69	2149.34	97.10	19.36

 

According to EFSA Guidance on Dermal Absorption (2012) as well as the EU Guidance Document

on Dermal Absorption (2004) only the first 2 tape strips should be discarded. On that basis dermal absorption for both low and high doses have been re-calculated.  

 

Recalculation disregarding 2 rather than 5 tape strips:

 

Prep 1 (20% a.i.)
	Cell 1	Cell 2	Cell 3	Cell 4	Cell 8	Cell 9	Cell 10	Cell 12	Cell 13	Cell 14	Mean	STDEV
1	0.008	0.019	0.08	0.068	0.18		0.282	0.12	0.023	0.144	0.103	0.090
2	0.003	0.011	0.141	0.099	0.093		0.295	0.063	0.01	0.201	0.102	0.098
Stratum total	0.04	0.1	0.99	0.69	0.95		1.58	0.62	0.16	1.33	0.718	0.549
minus 1+2	0.029	0.07	0.769	0.523	0.677		1.003	0.437	0.127	0.985	0.513	0.378
Dermal delivery	0.02	0.09	0.77	0.27	1.35		1.73	0.82	0.15	0.41	0.623	0.597
Absorbable Dose	0.049	0.16	1.539	0.793	2.027		2.733	1.257	0.277	1.395	1.137	0.907
Prep 2 (0.2% a.i.)
	Cell 16	Cell 17	Cell 18	Cell 19	Cell 24	Cell 25	Cell 26	Cell 28	Cell 29	Cell 30	Mean	STDEV
1	3.11	2.24	2.84	4.42	3.36	3.89	4.82	3.78	4.87	6.06	3.939	1.131
2	1.66	1.8	1.71	2.33	1.73	2.53	2.19	2.26	2.5	2.26	2.097	0.338
Stratum total	12.02	13.59	14.46	19.48	15.39	15.49	20.79	16.73	14.73	18.17	16.085	2.718
minus 1+2	7.25	9.55	9.91	12.73	10.3	9.07	13.78	10.69	7.36	9.85	10.049	2.052
Dermal delivery	2.56	2.52	3.84	3.15	8.21	9.37	6.12	7.47	3.15	4.02	5.041	2.538
Absorbable Dose	9.81	12.07	13.75	15.88	18.51	18.44	19.9	18.16	10.51	13.87	15.090	3.611

Conclusions:

The systemically available dose of the registration substance (= dermal delivery: exposed skin + absorbed dose) was 0.6 ± 0.6% for the high exposure scenario (20% a.i.), and 5.0±2.5% for the low exposure scenario (0.2% a.i.), respectively.
The potentially absorbable dose of the registration substance was 1.1 ± 0.9% for the high exposure scenario (20% a.i.), and 15.1 ± 3.6% for the low exposure scenario (0.2% a.i.), respectively.

Executive summary:

The percutaneous absorption of [¹⁴C]-Amines, N-C10 -16 -alkyltrimethylenedi-, reaction products with chloracetic acid was tested according toOECD 428: Skin Absorption: In Vitro Method (2004).

Split-thickness human skin membranes were mounted into flow-through diffusion cells. Receptor fluid, consisting of bovine serum albumin (ca. 5%), glucose (ca 1%), streptomycin (0.1 mg/mL), and penicillin G (100 U/mL), was pumped underneath the skin at a flow rate of ca 1.5 mL/h. Receptor fluid was collected in hourly fractions and analysed by liquid scintillation counting.

Test preparation 1, 20 % (w/w): Mass balance 101.69 % (SD = 3.04%), thus considered to be complete.

Absorbed dose: 0.01 % (0.18 ng equivalent/cm²)

Dermal delivery: 0.62 % (13.17 ng equivalent /cm²)

Potentially absorbable dose(sum of absorbed dose, exposed skin and stratum corneum tape strips 6–20): 0.97 % (20.53 ng equivalent /cm²)

Test preparation 2, 0.2 % (w/w): Mass balance 97.10 % (SD = 2.99%), thus considered to be complete.

Absorbed dose: 0.11 % (0.02 ng equivalent /cm²)

Dermal delivery: 5.04 % (1.01 ng equivalent /cm²)

Potentially absorbable dose (sum of absorbed dose, exposed skin and stratum corneum tape strips 6–20): 11.42 % (2.28 ng equivalent /cm²)

 

However, according to EFSA Guidance on Dermal Absorption (2012) as well as the EU Guidance Document on Dermal Absorption (2004) only the first 2 tape strips should be discarded. On that basis the potentially absorbable dose for both low and high doses has been re-calculated.  

The potentially absorbable dose (the sum of the absorbed dose, exposed skin and stratum corneum tape strips 3–20 may be used for risk assessment; this corresponds to 1.1 ±0.9% for the high exposure (20% a.i.), and 15.1±3.6% for the low exposure scenario (0.2 % a.i.), respectively.

For REACH-purposes the

"Dermal absorption represents the amount of topically applied test substance that is found in the epidermis (stratum corneum excluded) and in the dermis, and this quantity is therefore taken as systemically available. Dermal absorption is influenced by many factors, e.g. physico-chemical properties of the substance, its vehicle and concentration, and the exposure pattern (e.g. occlusion of the application site) as well as the skin site of the body (for review see ECETOC, 1993; Howes et al, 1996; Schaefer and Redelmaier, 1996). The term percutaneous penetration refers to in vitro experiments and represents the amount of topically applied test substance that is found in the receptor fluid – this quantity is taken as systemically available. " (Guidance on Information requirements and chemical safety assessment, R.7c).

Description of key information

Based on physicochemical properties and identified uses, the potential for inhalation of components of the registration substance either as vapour or dust appears marginal.
The oral bioavailability was determined to be 34% (OECD guideline 417, GLP; rat).
The systemically available dose after dermal administration was determined to be 0.6±0.6% for the high exposure scenario (20% a.i.), and 5.0±2.5% for the low exposure scenario (0.2% a.i.), respectively (OECD guideline 428, GLP; human skin).

Key value for chemical safety assessment

Bioaccumulation potential:

no bioaccumulation potential

Absorption rate - oral (%):

50

Absorption rate - dermal (%):

5

Absorption rate - inhalation (%):

100

Additional information

Inhalative absorption

The substance as a 20% aqueous solution of Amines, N-C10 -C16 -alkyltrimethylenedi-, reaction products with chloroacetic acid (“product by process”), is not volatile (vapour pressure < 1.9 × 10^–4 Pa). The substance is neither a powder nor is it to be included in powdery preparations. Furthermore, the substance is not intended to be applied in a manner leading to generation of aerosols, particles or droplets in the inhalable size range (MMAD < 50 µm). Therefore, the potential for inhalation of components of the registration substance either as vapour or dust appears marginal.

However, for chemical safety assessment by default 100% absorption will be assumed in accordance with REACH TGD as no experimental data concerning absorption after inhalative exposure are available.

 

Oral absorption

Absorption of [¹⁴C]- Amines, N-C10 -C16 -alkyltrimethylenedi-, reaction products with chloroacetic acid (20% a.i.) was investigated in the rat (OECD guideline 417). The test substance was administered orally by gavage at two single dose levels of 30 and 100 mg/kg bw, singly intravenous and orally at one repeated low dose level.

The systemic bioavailability, assessed by comparison of plasma radioactivity after oral and intravenous administration, was 34%.

This finding is also supported by the physicochemical properties: The registration substance is freely miscible with water (>200 g/L, according to the product being a 20% aqueous solution). In view of the amphoteric properties, the log Dow has been estimated by QSAR at 2.33. Consequently, the registration substance may be assumed to be readily dissolved in gastrointestinal fluids and subsequently available for passage through the epithelial barrier of the GI tract by passive diffusion.

Also the toxicological signs observed in the 90-d studies in rats at relatively low doses (approx. 3.0–20 mg a.i./kg bw/d) suggest high oral absorption. 

The Guidance on Information requirements and Chemical Safety Assessment, R.7c (Nov. 2012) states: “In practice, an adjustment in oral toxicity factor (to account for absorbed dose in the dermal exposure pathway) is recommended when the following conditions are met: (1) the toxicity value derived from the critical study is based on an administered dose (e.g., delivery in diet or by gavage) in its study design; (2) a scientifically defensible database demonstrates that the GI absorption of the chemical in question, from a medium (e.g., water, feed) similar to the one employed in the critical study, is significantly less than 100% (e.g., <50%). A cut-off of 50% GI absorption is recommended to reflect the intrinsic variability in the analysis of absorption studies. Thus, this cut-off level obviates the need to make comparatively small adjustments in the toxicity value that would otherwise impart on the process a level of accuracy that is not supported by the scientific literature.”

Thus an oral absorption of 50% will be used for chemical safety assessment.

 

Dermal absorption

The percutaneous absorption of [¹⁴C]-Amines, N-C10 -C16 -alkyltrimethylenedi-, reaction products with chloroacetic acid was tested according to OECD guideline 428 (A6.2/03) in an in vitro study at two different concentrations. It could be shown for a 20% test preparation (aqueous solution) that 99.76 % of the applied dose was removed from the skin by washing at 6 h post application. With a mass balance of 101.7% it was concluded that the absorbed dose, dermal delivery and potentially absorbable dose were 0.01 % (0.18 ng equivalent/cm²), 0.62 % (13.17 ng equivalent /cm²) and 0.97 % (20.53 ng equivalent /cm²), respectively. The second test preparation, 0.2% [¹⁴C]-Amines, N-C10 -C16 -alkyltrimethylenedi-, reaction products with chloroacetic acid

as aqueous solution, resulted in 73.66 % removable dose by washing at 6 h post application and 0.11 % (0.02 ng equivalent /cm²), 5.04 % (1.01 ng equivalent /cm²) and 11.42 % (2.28 ng equivalent /cm²) of the applied dose, absorbed dose, dermal delivery and potentially absorbable dose, respectively (97.1 % mass balance).

 

According to the Guidance on Information requirements and chemical safety assessment, R.7c: "Dermal absorption represents the amount of topically applied test substance that is found in the epidermis (stratum corneum excluded) and in the dermis, and this quantity is therefore taken as systemically available. Dermal absorption is influenced by many factors, e.g. physico-chemical properties of the substance, its vehicle and concentration, and the exposure pattern (e.g. occlusion of the application site) as well as the skin site of the body […]. The term percutaneous penetration refers to in vitro experiments and represents the amount of topically applied test substance that is found in the receptor fluid – this quantity is taken as systemically available."

 

Thus, the systemically available dose of the registration substance (= dermal delivery: exposed skin + absorbed dose) was 0.6 ± 0.6% for the high exposure scenario (20% a.i.), and 5.0 ± 2.5% for the low exposure scenario (0.2% a.i.), respectively. The high exposure scenario (20% a.i.) is relevant for chemical safety assessment of worker uses. A dermal absorption of 1% will be applied for those assessments.

The low exposure scenario (0.2% a.i.) is relevant for the chemical safety assessment of consumer uses. For those assessments, a dermal absorption of 5% will be applied.

Distribution, metabolism and excretion

Distribution, metabolism and excretion of [¹⁴C]-Amines, N-C10 -C16 -alkyltrimethylenedi-, reaction products with chloroacetic acid (20% a.i.) were investigated in the rat according to the OECD test guideline 417. The test substance was administered orally by gavage at two single dose levels of 30 and 100 mg/kg bw, singly intravenous and orally at one repeated low dose level.

Upon oral administration, radioacitivity was predominantly eliminated via faeces (approx. 60 %) and via expired air (approx. 18 %). A lower proportion was excreted via urine (approx. 9 %) and less than 20 % of the administered dose was found in the carcass. No significant differences of absorption and elimination of test substance regarding high or low dose, repeated administration or sex could be identified. The recovery of radioactivity was greatest in the residual carcass (12–19 %), followed by the liver (approx 4 %). In all other tissues the radioactive recovery was low (≤ 1.00 %) and quite uniformly distributed, with no tissue storage in brain, heart, ovaries and spinal cord. There was no relevant difference in the tissue distribution of radioactivity between animals treated orally or intravenously with a single or repeated dose of the test substance. The elimination half-life was approx. 74 hours both in the p.o. and i.v. group.

In plasma, only parent substances but no transformation products could be identified. A first-pass effect following intestinal absorption is therefore unlikely. In urine and faeces, parent substances as well as transformation products were detected. Metabolites in both urine and faeces were characterised by oxidation (hydroxylation) of the parent and some other metabolites like dehydrogenated and acetylated compounds. The most abundant compounds in urine were the oxidation products.