Triglycerides, C16-18 (even numbered), reaction products with diethylenetriamine

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics in vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1996

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Justification for type of information:

Pharmacokinetics and Material Balance Studies of Diethylenetriamine Trihydrochloride in the Fischer 344 Rat is presented due to potential release of Diethylenetriamine from the registered substance due to metabolic activation and presence of small quantities within the UVCB.

Data source

Reference

Reference Type:

publication

Title:

Pharmacokinetics and Material Balance Studies of Diethylenetriamine Trihydrochloride in the Fischer 344 Rat following Oral, Endotracheal or Intravenous Dosing

Author:

Hon-Wing Leung, Tipton R. Tyler

Year:

1997

Bibliographic source:

JOURNAL OF APPLIED TOXICOLOGY, VOL. 17(6), 361–367 (1997)

Materials and methods

Objective of study:

toxicokinetics

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 417 (Toxicokinetics)

Deviations:

yes

Principles of method if other than guideline:

Pharmacokinetics and Material Balance study of Diethylenetriamine Trihydrochloride in the Fischer 344 comparable to OECD 417 requirements.

GLP compliance:

not specified

Test material

Test material information

Test material form:

liquid

Details on test material:

[1,2-14C]-Diethylenetriamine trihydrochloride (14C-DETA·3HCl) with a specific activity of 6 mCi mmol−1 and a radiochemical purity of 98%.

Specific details on test material used for the study:

[1,2-14C]-Diethylenetriamine trihydrochloride (14C-DETA·3HCl) with a specific activity of 6 mCi mmol−1 and a radiochemical purity of 98% (CAS 3488-89-9).

Radiolabelling:

yes

Test animals

Species:

rat

Strain:

Fischer 344

Sex:

male

Details on test animals or test system and environmental conditions:

Male Fischer 344 rats, 36 days old, were obtained from Charles River Breeding Laboratories, Portage, MI. After a 9–14-day acclimation period, healthy animals were assigned to study groups based on a body-weight-stratified randomization procedure. Throughout the study rats were maintained on a 12-h light/dark cycle under controlled temperature and humidity conditions, and food and water were available ad libitum.

Administration / exposure

Route of administration:

other: Endotracheal, Intravenous and Oral

Vehicle:

other: unlabeled DETA and physiological saline

Duration and frequency of treatment / exposure:

Single dosing of animals

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

50 mg/kg bw/day (nominal)

Remarks:

Intravenous, oral and endotracheal route

Doses / concentrations 2

Dose / conc.:

500 mg/kg bw/day (nominal)

Remarks:

Oral and endotracheal route

No. of animals per sex per dose / concentration:

Dose route: Intravenous/Oral/Endotracheal
Number of rats: 4/5/4

Control animals:

no

Details on dosing and sampling:

Dosing solutions were prepared by mixing appropriate amounts of unlabeled DETA with [14C]-DETA·3HCl in physiological saline to provide target dosages of 50 and 500 mg kg−1 at a constant dosing volume of 0.25 ml per animal.
The dosing solutions were adjusted to pH 7.4 using hydrochloric acid or ammonium hydroxide, as required. Animals in the pharmacokinetics study groups had an indwelling cannula implanted in the right jugular vein1 day prior to dosing. Intravenous dosing was accomplished by injecting
the tail vein. Oral dosing was performed with a stainless-steel feeding needle, and endotracheal instillation was achieved by injecting through a small polyethylene tube into the trachea of rats under light anesthesia with Metofane.

For the material balance study, the animals were placed in all-glass Roth metabolism cages immediately after dosing. Expired 14CO2 was trapped using a solution of 2-methoxyethanol–ethanolamine (7:3, v/v) and sampled for radioactivity 6, 24 and 48 h after dosing. Urine and feces were collected 24 and 48 h after dose administration. Cages were washed with a 50% aqueous acetone solution and samples of the wash solution
were taken for radiometric analysis. Blood was obtained from the abdominal aorta 48 h after dosing. Animals were killed by exsanguination after collection of the last blood and excreta samples. Selected tissues were removed, sampled and analyzed for radioactivity. The remaining carcasses were solubilized in 10 N NaOH and samples of this solution were also analyzed for radioactivity. For the pharmacokinetics study, rats
were placed in stainless-steel wire metabolism cages. Blood samples (about 0.2 ml) were taken via the jugular cannulae at 5, 15, 30 and 45 min and at 1, 2, 3, 4, 5, 6, 8, 10, 12, 16 and 24 h after dosing.

The amount of radioactivity in various samples was measured by liquid scintillation spectrometry. Blood was centrifuged in heparinized capillary tubes to separate into plasma and packed red cells. Portions of other liquid samples, such as plasma, urine and cage washes, were weighed directly into scintillation vials containing 10 ml of Aquasol (New England Nuclear, Boston, MA). Samples of the CO2 trapping solution and solubilized carcass were weighed directly into scintillation vials and counted in a solution of equal volumes of 2-methoxyethanol, dioxane and xylene containing 160:120:1 (w/w/w) of naphthalene, 2,5-diphenyloxazole and 2,2-p-phenylenebis-(5-phenyloxazole). Feces and tissues were solubilized in Soluene 350 (Packard Instrument Co., Downers Grove, IL), oxidized with 30% H2O2 and counted with 10 ml of Dimilume 30 (Packard Instrument Co., Downers Grove, IL).

Statistics:

Curve fitting of the pharmacokinetic data was performed by hand feathering or with the aid of ESTRIP. Parameters estimated included area under the concentration–time curve to infinite time (AUC`), total clearance and terminal half-lives. The maximal plasma concentration (Cmax) and time to maximal plasma concentration (tCmax) following oral or endotracheal dosing were estimated from the concentration–time course equation by the Newton–Raphson method of numerical analysis.

Results and discussion

Main ADME results

Main ADME results 1

Type:

absorption

Results:

The bioavailability was over 90%. [14C]-DETA·3HCl was well absorbed following oral or endotracheal dosing. Clearance of absorbed [14C]- DETA·CHCl from the plasma was also rapid, with a terminal half-life of 9-16 h.

Main ADME results 2

Type:

distribution

Results:

The highest radioactivity concentrations of DETA was attained in the liver and kidney, suggesting that these organs are common targets for this alkyleneamine

Main ADME results 3

Type:

metabolism

Results:

Metabolism of [14C]-DETA·3HCl appeared to play a small role in the elimination of DETA from the body, as unchanged DETA was the principal component excreted in the urine.

Main ADME results 4

Type:

excretion

Results:

The major excretory route of DETA was via the urine and feces. These two pathways together accounted for over 70% of the total dose excreted.

Toxicokinetic / pharmacokinetic studies

Details on distribution in tissues:

Material balance of radioactivity in Fischer 344 rats at 48 h following an oral or endotracheal dose of [14C]-diethylenetriamine trihydrochloride

Dose route Oral Endotracheal
Targeted dosage (mg kg-1) 50 500 50 500
Body weight (kg) 0.169 ± 0.006 0.202 ± 0.013 0.171 ± 0.007 0.202 ± 0.004
Radioactivity (mCi) 7.5 ± 0.3 10.2 ± 0.2 7.8 ± 0.15 9.6 ± 0.10
Dose (mg) 8.2 ± 0.3 102.8 ± 2.5 8.5 ± 0.1 97.2 ± 0.9
Dosage (mg kg-1) 48.2 ± 2.7 511 ± 29.5 49.5 ± 2.0 81 ± 5.5
(Per cent of dosed radioactivity)
Urine 31.1 ± 2.5 42.9 ± 9.3 32.2 ± 9.2 40.3 ± 9.5
Feces 45.6 ± 2.1 44.2 ± 1.3 39.7 ± 8.7 45.5 ± 8.4
CO2 1.09 ± 0.10 0.52 ± 0.04 1.28 ± 0.18 0.57 ± 0.12
Cage washings 5.4 ± 4.9 10.1 ± 5.6 8.0 ± 2.6 14.1 ± 6.2
Carcass 2.0 ± 0.4 1.8 ± 0.1 3.1 ± 0.6 2.1 ± 0.4
Total recovery 85.2 ± 4.3 99.6 ± 3.3 84.3 ± 4.4 102.8 ± 1.2

Toxicokinetic parameters

Toxicokinetic parameters 1

Key result

Test no.:

#1

Toxicokinetic parameters:

AUC: 62.2 ± 16.9 mg·h ml-1

Remarks:

intravenous route

Toxicokinetic parameters 2

Key result

Test no.:

#2

Toxicokinetic parameters:

AUC: 59.1 ± 4.1 mg·h ml-1

Remarks:

oral route

Toxicokinetic parameters 3

Key result

Test no.:

#3

Toxicokinetic parameters:

AUC: 56.0 ± 9.1 mg·h ml-1

Remarks:

endotracheal route

Toxicokinetic parameters 4

Key result

Test no.:

#1

Toxicokinetic parameters:

Cmax: 120 ± 21 mg ml-1

Remarks:

intravenous route

Toxicokinetic parameters 5

Key result

Test no.:

#2

Toxicokinetic parameters:

Cmax: 13.83 ± 3.97 mg ml-1

Remarks:

oral route

Toxicokinetic parameters 6

Key result

Test no.:

#3

Toxicokinetic parameters:

Cmax: 10.83± 3.62 mg ml-1

Remarks:

endotracheal route

Metabolite characterisation studies

Metabolites identified:

not specified

Any other information on results incl. tables

DETA·3HCl-derived radioactivity concentrations in the plasma could best be described by a tri-exponential

equation of the form C = 119.6e−8.49t + 69.4e−2.07t + 2.4e−0.12t . The maximal plasma concentration

(Cmax) was 120 ± 21 mg ml−1 and the apparent volume of distribution (Vd) was 486 ± 220 ml kg−1. In rats

dosed orally or endotracheally, the peak concentration was generally attained within 1 h following dosing , suggesting that absorption of [14C]- DETA·3HCl from the gut or the respiratory tract was quite rapid. The bioavailability was over 90%, suggesting that [14C]-DETA·3HCl was well absorbed following oral or endotracheal dosing. Clearance of absorbed [14C]-DETA·CHCl from the plasma was also rapid, with a terminal half-life of 9–16 h. Fecal excretion was the major route of excretion, followed closely by elimination in the urine. Only a small percentage of the dose was reco-

vered as expired CO2 or was retained in the tissues and carcasses. No significant differences in the percent-

ages of radioactivity excreted in the urine, feces or CO2 were observed between animals dosed orally or endotracheally. The DETA was distributed throughout the body, with the highest concentrations found in the kidney and liver. The mean concentration for all tissues in the 500 mg kg−1 group was about 7.5 times that in the 50 mg kg−1 group. This was slightly lower than the 10-fold difference in dosages. Similar to the excretion data, there was no indication that route of administration had any significant effect on tissue concentrations.

Table 1.  Dosages  and  pharmacokinetic  parameters  in  Fischer  344  rats  following intravenous,  oral   and   endotracheal  dosing   with  [14C]-diethylenetriamine  trihydrochloride

Dose route	Intravenous	Oral	Endotracheal
Number of rats	4	5	4
Body weight  (kg)	0.185 ± 0.005	0.178 ± 0.016	0.183 ± 0.002
Radioactivity (mCi)	48.7 ± 0.3	30.3 ± 0.4	30.6 ± 0.5
Dose (mg)	10.30 ± 0.08	8.33 ± 0.12	8.41 ± 0.14
Dosage (mg kg−1)	55.6 ± 1.9	46.8 ± 4.3	45.8 ± 1.2
Cmax  (mg ml−1)	120 ± 21	13.83 ± 3.97	10.83± 3.62
tCmax (h)	-	0.77 ± 0.38	0.77 ± 0.36
Vd  (ml kg−1)	486 ± 220	-	-
AUC`  (mg·h ml−1)	62.2 ± 16.9	59.1 ± 4.1	56.0 ± 9.1
Bioavailability  (%)	-	95.0	90.0
Total  clearance (ml h−1)	174 ± 44	134 ± 10	138 ± 23
Terminal  t1/2  (h)	9.7 ± 5.3	16.3 ± 6.1	9.0 ± 5.0

Applicant's summary and conclusion

Conclusions:

Metabolism of [14C]-DETA·3HCl appeared to play a small role in the elimination of DETA from the body, as unchanged DETA was the principal component excreted in the urine. The major excretory route of DETA was via the urine and feces. These two pathways together accounted for over 70% of the total dose excreted. The highest radioactivity concentrations of DETA was attained in the liver and kidney, suggesting that these organs are common targets for this alkyleneamine.

Executive summary:

In the Klimisch 2 publication from Leung (1997) the pharmacokinetics and material balance of diethylenetriamine trihydrochloride ([14C]-DETA·3HCl) in the Fischer 344 rat following oral, endotracheal or intravenous dosing was studied comparabel to an OECD Guideline for Testing of Chemicals No. 417 (2010) study. The bioavailability of [14C]-DETA·3HCl was over 90%. [14C]-DETA·3HCl was well absorbed following oral or endotracheal dosing. Clearance of absorbed [14C]- DETA·3HCl from the plasma was also rapid, with a terminal half-life of 9-16 h. The highest radioactivity concentrations of [14C]- DETA·3HCl was attained in the liver and kidney, suggesting that these organs were common targets for these two alkyleneamines. Metabolism of [14C]-DETA·3HCl appeared to play a small role in the elimination of DETA from the body, as unchanged DETA was the principal component excreted in the urine. The major excretory route of DETA was via the urine and feces. These two pathways together accounted for over 70% of the total dose excreted.