N-(3-aminopropyl)-N-dodecylpropane-1,3-diamine

Endpoint summary

Link to relevant study record(s)

Reference

Endpoint:

basic toxicokinetics in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From January 10, 1996 to August 07, 1996

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Objective of study:

toxicokinetics

Qualifier:

according to guideline

Guideline:

OECD Guideline 417 (Toxicokinetics)

GLP compliance:

yes (incl. QA statement)

Radiolabelling:

yes

Remarks:

14C

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan UK, Bicester, Oxfordshire, UK
- Age at study initiation: ca. 6-10 weeks
- Weight at study initiation: ca. 200 g
- Housing: During acclimatisation in stainless steel cages with suspended mesh floor. Rats from excretion study were housed in individual glass metabolism cages, rats from other studies (blood/plasma kinetics and tissue distribution) in stainless steel battery cages (25 x 25 x 50 cm).
- Individual metabolism cages: Yes
- Diet (e.g. ad libitum): Standard Laboratory Rat LAD 1, ad libitum
- Water: Ad libitum
- Acclimation period: At least 5 d

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-23
- Humidity (%): 40-60
- Photoperiod (hrs dark / hrs light): 12 / 12

Route of administration:

oral: gavage

Vehicle:

unchanged (no vehicle)

Duration and frequency of treatment / exposure:

Single dose

Dose / conc.:

3 mg/kg bw/day (actual dose received)

Dose / conc.:

30 mg/kg bw/day (actual dose received)

No. of animals per sex per dose / concentration:

Excretion studies: Eight rats (4 male, 4 female) received single oral doses of 14C-test substance at a nominal dose level of 3 mg/kg bw and 30 mg/kg bw each
Blood/plasma kinetics: Eighteen animals (9 male, 9 female) received single oral doses 3 mg/kg bw and 30 mg/kg bw each of 14C-test substance
Quantitative tissue distribution: Five male rats received single oral doses (nominal 3 mg/kg bw) of 14C-test substance

Control animals:

no

Details on study design:

- Dose selection rationale: Based on the oral LD50 value in rats of 261 mg/kg bw, an approximately ten-fold lower dose level of 30 mg/kg bw was selected as suitable for the high dose level. A further ten-fold lower dose level of 3 mg/kg bw was selected for the low dose level at which no toxic effects are expected.

Details on dosing and sampling:

PHARMACOKINETIC STUDY (Absorption, distribution, excretion)
- Tissues and body fluids sampled: Urine, faeces, expired air, blood, cage wash
- Time and frequency of sampling: Urine was collected at 0-6 and 6-24 h after dosing and then at 24 h interval up to 120 h. Faeces were collected at 24 h interval for 120 h. Expired air was collected at 24 h interval for 48 h. Cages were washed at 120 h.

BLOOD/PLASMA kinetics:
- Time and frequency of sampling: Blood was taken from a tail vein at following intervals:
Group 1: Pre-dose, 14, 24 and 96 h. Group 2: 0.25, 2, 6, 48 and 120 h. Group 3: 0.5, 3, 12, 72 and 168 h.

QUALITATIVE TISSUE DISTRIBUTION:
- Time and frequency of sampling: At 3, 6, 24, 48 and 120 h post-administration sacrifice.

ANALYTICAL METHODS:
- Samples of urine, plasma, solvent extracts, contents of expired air traps, cage washings and other liquid samples were mixed with special scintillator MI-31 for measurement of radioactivity by liquid scintillation counting (LSC).
- Samples of fecal extracts were pooled to give representative samples and analysed directly by TLC.
- Metabolites were quantified using TLC (i.e., radiolabelled metabolite products formed in the rat were identified by co-chromatographic comparison using different systems with the reference compound 1-dodecylamine and authentic test substance).

Preliminary studies:

No visible toxic effects were observed in the 4 rats that received a single oral dose of 30 mg/kg bw of non-radiolabelled test substance. The high dose was confirmed as 30 mg/kg bw.

Type:

absorption

Results:

The gastrointestinal absorption is considered to be 2.5% based on a retained dose.

Type:

distribution

Results:

High levels of radioactivity in the gastrointestinal tract and its contents

Type:

metabolism

Results:

Major component of the faecal extracts was unchanged test substance accounting for 7-13%; six minor components (including 1-dodecylamine) were also observed in fecal extracts each accounting for 1-3% dose.

Type:

excretion

Results:

90-97% was excreted in faeces, approximately 0.2% of the dose was excreted in the urine and <0.4% of the dose was in expired air traps

Details on absorption:

Low level doses:
After single low level doses of 14C-test substance to three groups of six rats (3 male, 3 female), peak of mean concentrations of radioactivity in plasma were below the limit of reliable measurement. Peak plasma concentration occurred at 4 h after administration of the test substance.

High level doses:
After single high level doses of 14C-test substance to three groups of six rats (3 male, 3 female), peak of mean concentrations of radioactivity in plasma of 0.12 (male) and 0.12 (female) µg equiv./ml occurred at 12 h. Concentrations declined with an approximate half-life (measured between 12 and 48 h) of 28.5 (male) and 46.3 (female) h. The area under the concentration v time curve (AUCt) was 4.6 (male) and 5.1 (female) µg equiv./mL.h.

Details on distribution in tissues:

- At 3 h after administration of the 14C-test substance at a nominal dose level of 3 mg/kg bw, high concentrations of radioactivity were detected in the oesophagus as well as in the contents of the caecum, small intestine and stomach. Intermediate concentrations of radioactivity were detected in the bladder. Lowest concentrations of radioactivity were detected in the adrenals, blood, kidney, large intestine contents, liver, lungs, pancreas, salivary gland and spleen.

- At 6 h after administration, high concentrations of radioactivity were detected in the oesophagus as well as in the contents of the caecum, small intestine and stomach. Intermediate concentrations of radioactivity were detected in the kidney, liver, lungs and spleen. Lowest levels of radioactivity were detected in the adrenals, brown fat, blood, bone marrow, exorbital lachrymal gland, myocardium, pancreas, preputial gland, pituitary gland, salivary gland, thymus and thyroid.

- At 24 h after administration, high concentrations of radioactivity were detected in the contents of the caecum, large intestine and stomach. Intermediate concentrations of radioactivity were detected in the adrenals, brown fat, Harderian gland, kidney, liver, lung, myocardium, preputial gland, oesophagus, small intestine contents, salivary gland and spleen. Lowest levels of radioactivity were in the blood, bone marrow, exorbital lachrymal gland, intra-orbital lachrymal gland, pancreas, pituitary, thymus and thyroid.

- At 48 h after administration, high levels of radioactivity were detected in the contents of the caecum, the large intestine and the large intestine mucosa. Intermediate concentrations of radioactivity were detected in the kidney, lung, small intestine contents, small intestine mucosa, spleen, stomach contents and stomach mucosa. Lowest concentrations of radioactivity were detected in the adrenals, blood, bone marrow, exorbital lachrymal gland, Harderian gland, intra-orbital lachrymal gland, liver, myocardium, pancreas, preputial gland, pituitary gland, salivary gland and thymus.

- At 120 h after administration, intermediate concentrations of radioactivity were detected in the kidney, lung, pancreas, salivary gland, smal intestine mucosa, spleen and stomach mucosa. Lowest levels of radioactivity were detected in the adrenals, blood, bone marrow, exorbital lachrymal gland, Harderian gland, liver, intra-orbital lachrymal gland, muscle, myocardium, pituitary gland, thymus, testes and thyroid.

Details on excretion:

Low level dose:
- After a single low level oral dose of 14C-test substance to rats (4 male, 4 female), means of 0.2 % (male) and 0.2% (female) were excreted in the urine during 0 – 120 h. Most of this radioactivity was excreted in the 0 – 48 h urine (0.1% for both male and female).
- During the 5 d after dosing 97% (male) and 96% (female) was excreted in the faeces with most of this in the 0 – 72 h samples (97 % male, 95% female).
- Radioactivity in expired air traps was measured over 48 h and accounted for 0.1 % (male) and 0.2 % (female) dose.
- After sacrifice at 120 h radioactivity in the gastrointestinal tract accounted for 0.5% (male) and 0.4 % (female) dose whilst radioactivity in the remaining carcass accounted for 1.0 % (male) and 1.5 % (female) dose. Thus, means of 99 % (male) and 98 % (female) were recovered after 5 d.

High level dose:
- After a single high level oral dose of 14C-test substance to rats (4 male, 4 female), means of 0.2% (male) and 0.2% (female) were excreted in the urine during 0 – 120 h. Most of this radioactivity was excreted in the 0 – 48 h urine (0.2 % for male and 0.1 % for female).
- During the 5 d after dosing 95 % (male) and 90% (female dose) was excreted in the faeces with most of this in the 0 – 72 hour samples (95 % male, 89 % female).- Radioactivity in expired air traps was measured over 48 h and accounted for 0.4 % (male) and 0.4 % (female) dose.
- After sacrifice at 120 h radioactivity in the gastrointestinal tract accounted for 1.2 % (male) and 1.3% (female) dose whilst radioactivity in the remaining carcass accounted for 3.0 % (male) and 2.6 % (female) dose. Thus, means of 100 % (male) and 94 % (female) were recovered after 5 d.

Metabolites identified:

yes

Details on metabolites:

Metabolites were quantified using TLC. Samples of faecal extracts were analysed directly. Urine was not analysed as the total radioactivity excreted in the urine was < 0.3%.
Faecal extracts:
- In the 0 – 48 h faecal extracts of rats after administration of 14C-test substance there was one major radioactive component that accounted for 7 – 13% dose (39 – 51% sample radioactivity). This component co-chromatographed with authentic test substance in two TLC systems.
- Six further minor components were detected in faecal extracts accounting for 1 –3% dose after both low and high level doses. One of these components was shown to co-chromatograph with 1-dodecylamine using TLC. The nature of the other components was not investigated further due to the low levels of radioactivity involved (<3% dose).
- A large proportion of the dose (66 – 72%) remained unextracted after both low and high level doses. Further extraction with 1M HCl and 2M NaOH extracted a further 17 – 20% (low level) and 20 –25% (high level) dose. Attempts to analyses these extracts (after neutralisation) were unsuccessful.

After single oral doses of 14C-test substance approximately 0.2 % of the dose was excreted in the urine. Approximately 90-97 % dose was excreted in faeces during 5 days. At sacrifice approximately 1-3 % dose was retained in the carcass and 0.4 - 1.3 % of the dose was recovered in the gastrointestinal tract. Radioactivity in expired air traps accounted for 0.4 % dose. There was no noticeable difference in excretion after the different dosing regimens or between male and female rats. This indicated that an average of 2.5 % of the initial dose was not excreted. 

Concentrations in plasma were consistent with low absorption of the test substance from the gastrointestinal tract. After low level doses, concentrations were generally below the limit of reliable measurement and appeared to peak 4 h after dose administration. After high level doses, concentrations of radioactivity in plasma were again low with values generally less than twice the limit of reliable measurement. The plasma concentrations of radioactivity indicated a fairly rapid clearance of radioactivity with peak concentrations measured 12 h after dosing.

Qualitative analysis of the tissue distribution of radioactivity by whole- body autoradiography indicated high levels of radioactivity in the gastrointestinal tract and its contents. Levels of radioactivity observed in other tissues were consistent with low absorption from the gastrointestinal tract.

The major component in faecal extracts was unchanged test substance, accounting for 7-13 % dose. The assignment was confirmed by co-chromatography using TLC. Six minor components were also observed in faecal extracts, each accounting for 1 -3 % dose. One of these was shown to co-chromatograph with 1-dodecylamine. As the liver showed constant less activity then the kidney in all radiographs, significant entero-hepatic circulation can be excluded.

Conclusions:

Under the study conditions, the test substance was found to have a low absorption potential, to distribute mainly in the GIT and to be excreted primarily through faeces. Further, the faecal extracts majorly contained the unchanged test substance and 1-dodecylamine as one of the minor components.

Executive summary:

An in vivo basic toxicokinetic study was conducted to determine the absorption, distribution, metabolism and excretion of the test substance in Sprague Dawley rats according to OECD Guideline 417, in compliance with GLP. Groups of 9 male and female and 4 male and female rats were administered single oral (gavage) doses of 3 or 30 mg/kg bw of the radiolabelled test substance in the blood/plasma kinetics and excretion studies, respectively, and 5 male rats were administered a single oral dose of 3 mg/kg bw in the quantitative tissue distribution study. None of the animals showed signs of systemic toxicity.

Absorption: After administration of single oral doses of the radiolabelled test substance, the radioactivity excreted in the urine was about 0.2%. Approximately 90-97% of the dose was excreted in faeces during 5 d. At sacrifice, approximately 1-3% of the dose was retained in the carcass and 0.-1.3% of the dose was recovered in the gastrointestinal tract. Concentrations in plasma were consistent with low absorption of the test substance from the gastrointestinal tract. After low level doses, concentrations were generally below the limit of reliable measurement and appeared to peak at 4 h (Cmax) after dose administration. After high level doses, concentrations of radioactivity in plasma were again low with values generally less than twice the limit of reliable measurement. The plasma concentrations of radioactivity indicated a fairly rapid clearance of radioactivity with peak concentrations measured 12 h (Cmax) after dosing.

Distribution: Qualitative analysis of the tissue distribution of radioactivity by whole- body autoradiography indicated high levels of radioactivity in the gastrointestinal tract and its contents. Levels of radioactivity observed in other tissues were consistent with low absorption from the gastrointestinal tract.

Metabolism: The major component in faecal extracts was unchanged substance, accounting for 7-13% of the dose. The assignment was confirmed by co-chromatography using TLC. Six minor components were also observed in faecal extracts, each accounting for 1-3% of the dose. One of these was shown to co-chromatograph with 1-dodecylamine.

Excretion: Over a period of 5 d, the majority of the administered dose (90-97%) was excreted in faeces, approximately 0.2% was excreted in urine and radioactivity in expired air traps accounted for <0.4%. At necropsy, 1-3% of the dose was retained in the carcass and 0.4-1.3% was recovered in the gastrointestinal tract. This left about 2.5% of the initial dose that was not excreted. There was no noticeable difference in excretion after the different dosing regimens or between male and female rats. As the liver showed constant lower activity than the kidneys in all radiographs, significant entero-hepatic circulation was excluded.

Under the study conditions, the test substance was found to have a low absorption potential, to distribute mainly in the GIT and to be excreted primarily through faeces. Further, faecal extracts majorly contained the unchanged test substance and 1-dodecylamine as one of the minor components (McEwen, 1996).

Key value for chemical safety assessment

Bioaccumulation potential:

low bioaccumulation potential

Absorption rate - oral (%):

2.5

Absorption rate - dermal (%):

0.031

Absorption rate - inhalation (%):

2.5

Additional information

Oral absorption

An in vivo basic toxicokinetic study was conducted to determine the absorption, distribution, metabolism and excretion of the test substance in Sprague Dawley rats according to OECD Guideline 417, in compliance with GLP. Groups of 9 male and female and 4 male and female rats were administered single oral (gavage) doses of 3 or 30 mg/kg bw of the radiolabelled test substance in the blood/plasma kinetics and excretion studies, respectively, and 5 male rats were administered a single oral dose of 3 mg/kg bw in the quantitative tissue distribution study. None of the animals showed signs of systemic toxicity.

Absorption: After administration of single oral doses of the radiolabelled test substance, the radioactivity excreted in the urine was about 0.2%. Approximately 90-97% of the dose was excreted in faeces during 5 d. At sacrifice, approximately 1-3% of the dose was retained in the carcass and 0.-1.3% of the dose was recovered in the gastrointestinal tract. Concentrations in plasma were consistent with low absorption of the test substance from the gastrointestinal tract. After low level doses, concentrations were generally below the limit of reliable measurement and appeared to peak at 4 h (Cmax) after dose administration. After high level doses, concentrations of radioactivity in plasma were again low with values generally less than twice the limit of reliable measurement. The plasma concentrations of radioactivity indicated a fairly rapid clearance of radioactivity with peak concentrations measured 12 h (Cmax) after dosing.

Distribution: Qualitative analysis of the tissue distribution of radioactivity by whole- body autoradiography indicated high levels of radioactivity in the gastrointestinal tract and its contents. Levels of radioactivity observed in other tissues were consistent with low absorption from the gastrointestinal tract.

Metabolism: The major component in faecal extracts was unchanged substance, accounting for 7-13% of the dose. The assignment was confirmed by co-chromatography using TLC. Six minor components were also observed in faecal extracts, each accounting for 1-3% of the dose. One of these was shown to co-chromatograph with 1-dodecylamine.

Excretion: Over a period of 5 d, the majority of the administered dose (90-97%) was excreted in faeces, approximately 0.2% was excreted in urine and radioactivity in expired air traps accounted for <0.4%. At necropsy, 1-3% of the dose was retained in the carcass and 0.4-1.3% was recovered in the gastrointestinal tract. This left about 2.5% of the initial dose that was not excreted. There was no noticeable difference in excretion after the different dosing regimens or between male and female rats. As the liver showed constant lower activity than the kidneys in all radiographs, significant entero-hepatic circulation was excluded.

Under the study conditions, the test substance was found to have a low absorption potential, to distribute mainly in the GIT and to be excreted primarily through faeces. Further, faecal extracts majorly contained the unchanged test substance and 1-dodecylamine as one of the minor components (McEwen, 1996).

 

Dermal absorption

An in vitro study was conducted to determine the absorption potential of the test substance at an incorporation rate of 1% using human skin according to OECD Guideline 428, in compliance with GLP. 6.4 μL of the radiolabelled test substance in water was applied to the stratum corneum of each of 11 human skin samples. Absorption was assessed by collecting receptor fluid in hourly intervals from 0-6 h post dose and then in 2 h intervals from 6-24 h post dose. At 24 h post dose, the exposure was terminated by washing and drying the skin. The stratum corneum was then removed from the skin by 24 successive tape strips. All samples were analysed by liquid scintillation counting. Percutaneous absorption was 0.92% after 24 h. Only less than 0.01% completely passed the skin and 0.92% of the applied dose passed the stratum corneum but remained fixed in the skin after 24 h. This demonstrates a low dermal absorption as well as a low dermal mobility. The mean mass balance was 102.14% of the applied dose. At 24 h post dose, 73.32% of the applied dose was washed off. A further 5.09% of the applied dose was contained in the cell wash. Radioactivity associated with the stratum corneum was 22.82%. The absorbed dose (0.0 1%) was made up from the receptor fluid (0.01%) and the receptor rinse (0.01%). Dermal delivery (0.92%) was made up from the absorbed dose, exposed skin (0.91%) and unexposed skin (0.01%). Under the study conditions, the percutaneous absorption of the test substance was 0.92% after 24 h. Further, considering the steady state flux value of 0.0004% per h, it seems both unreasonable and scientifically unjustifiable to include the stratum corneum value of 23% in the dermal absorption (Roper, 2003).

A study was conducted to determine dermal absorption of the test substance using the non-compartmental pharmacokinetic analysis with WinNonlinTM. Equivalent doses of 14C-labelled test substance were administrated to rats by oral gavage or topical routes of administration. Blood samples were collected at 0.5, 1, 2, 4, 8 and 24 h after administration. Total radioactivity in each sample was reported and converted to µg-equivalents of active substance per ml of blood. Intravenous injection of test substance allowed to assess the dermal and gastrointestinal absorptions based on AUC comparisons. Under the study conditions, absorption of the test substance following dermal administration appeared to be 80 times lower than following oral administration (Johnson, 2000; van Miller, 2005).