1,4-Cyclohexanedicarboxylic acid, 1,4-diisononyl ester

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics in vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

15.02.2018 - 21.02.2019

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:

study report

Title:

Unnamed

Year:

2019

Report date:

2019

Materials and methods

Objective of study:

excretion

metabolism

toxicokinetics

Test guideline

Qualifier:

no guideline followed

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

1,4-bis(7-methyloctyl) cyclohexane-1,4-dicarboxylate

Cas Number:

313644-32-5

Molecular formula:

C26H48O4

IUPAC Name:

1,4-bis(7-methyloctyl) cyclohexane-1,4-dicarboxylate

Test material form:

liquid

Radiolabelling:

no

Test animals

Species:

rat

Strain:

Sprague-Dawley

Details on species / strain selection:

CD® / Crl:CD(SD)

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories Germany GmbH
- Age at study initiation: Stagger 1: 58 days
Stagger 2: 42 days
- Weight at study initiation: Stagger 1: 355.2 to 393.0 g
Stagger 2: 286.1 to 317.8 g
- Housing: The animals were kept singly in MAKROLON cages (type III plus) with a basal
surface of approximately 39 cm x 23 cm and a height of approximately 18 cm.
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 9 days per stagger

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22°C ±3°C
- Humidity (%): 55% ±10%
- Photoperiod (hrs dark / hrs light):The rooms were lit (about 150 lux at approx. 1.5 metres room height) and
darkened for periods of 12 hours each.

IN-LIFE DATES:
From: Test item administration Stagger 1: 16 February 2018
Stagger 2: 13 July 2018
To:Termination of in-life period Stagger 1: 17 February 2018
Stagger 2: 14 July 2018

Administration / exposure

Route of administration:

intravenous

Vehicle:

other: Stagger 1: 0.9% NaCl solution, Stagger 2: 5% Tween 80® in 0.9% NaCl solution

Duration and frequency of treatment / exposure:

Single dose on test day 1

Doses / concentrations

Dose / conc.:

100 mg/kg bw/day

Remarks:

Group 1 and 2

No. of animals per sex per dose / concentration:

16 male animals, allocated to 2 separate staggers
(8 animals per stagger).
Each stagger consisted of 2 groups (4 animals per
group).
Group 1: scheduled for PK sampling
Group 2: scheduled for urine sampling.

Control animals:

no

Details on study design:

- Dose selection rationale:

The dose level for this study has been selected by the Sponsor based on available
data and the results of LPT study 35156.
In this study, 2 male rats were treated once intravenously with 10 mg DINCD/kg
b.w. on test day 1.
None of the two male rats treated intravenously with 10 mg DINCD/kg b.w. died
prematurely during the course of the study. No abnormalities in behaviour, external
appearance, or condition of faeces were observed.

Details on dosing and sampling:

TOXICOKINETIC STUDY (Absorption, distribution, excretion)
- Tissues and body fluids sampled: urine, blood
- Time and frequency of sampling:
Blood sampling time after dosing [hh:mm p.a.]: 00:05, 00:10, 00:20. 00:40, 01:20, 02:40
Urine sampling: Urine was collected for a period of 24 hours p.a.

METABOLITE CHARACTERISATION STUDIES
- Tissues and body fluids sampled: urine, blood
- Time and frequency of sampling: see above
- From how many animals: (samples pooled or not)
Blood sampling: Sampling from animal no. 1 – 4 and 9 – 12. Blod samples were pooled.
Urine sampling: Sampling from animal no .5 – 8 and 13 – 16 (group 2; stagger 1 and 2)

- Method type(s) for identification: semiquantitative HPLC-MS-MS and HPLC-MS-MS
- Limits of detection and quantification:
LLOQ for HPLC-MS-MS: 20 ng/mL for DINCD and its metabolite.
LLOQ for semiquantitative HPLC-MS-MS: 20 ng/mL for DINCD and 400 ng/mL of its metabolite.
- Other: The samples were analysed at Prolytic GmbH, Alt-Fechenheim 34, 60386 Frankfurt, Germany

Statistics:

No statistical evaluation was performed.

Results and discussion

Toxicokinetic / pharmacokinetic studies

Transfer into organs

Observation:

not determined

Details on excretion:

The analysis of the urine samples by a semi-quantitative HPLC-MS/MS method
was the responsibility of the analytical laboratory.
Stagger 1
The analysis of the urine samples was postponed as hardly any test substance or
metabolite levels were detected in the plasma samples.
Stagger 2
Sample analysis was carried out on urine samples taken during a sampling period of
0 to 24 hours p.a.
In 3 of 4 animals, DINCD analyte concentrations were below the detection limit of
20 ng/mL. In one animal (animal no. 15) DINCD was determined in a concentration
of 940 ng/mL urine.
Quantification of the metabolite CHDCA in the urine samples revealed analyte
concentrations above the calibration range (i.e. >4000 ng/mL urine). Further
dilution of the urine samples into the calibration range was not advisable due to the
higher impact of matrix effects on the analytical results.

Toxicokinetic parameters

Key result

Toxicokinetic parameters:

Cmax: The maximum DINCD in plasma concentrations determined 5 minutes post administration (p.a.) ranged from 2727.73 to 4229.63 ng/ml (3380.52 ± 769.95 ng/ml) for animal nos. 9 to 11.

Metabolite characterisation studies

Metabolites identified:

yes

Details on metabolites:

The metabolite CHDCA (cis- 1,4-cyclohexanedicarboxylic acid) was also detected and quantified in the plasma of all
animals treated once intravenously with 100 mg DINCD/kg b.w. Metabolite plasma
concentrations increased steadily with a peak value determined between 80 and
160 minutes p.a. (80 minutes p.a.: 540.22 ± 416.85 ng/ml; 160 minutes p.a.:
327.54 ±16.41 ng/ml).

Applicant's summary and conclusion

Conclusions:

The toxikokinetik study of Diisononyl
1,4-cyclohexanedicarboxylate (DINCD) following
a single intravenous bolus injection to male rats generates qualitative and only orienting results.
In the preliminary test, DINCD was insoluble in 0.9% NaCl (stability and solubility problems).
The suitable solvent for i.v.injection in the main experiment was 5% Tween 80 in 0.9% NaCl.
The results show a metabolism of DINCD to a metabolite (cyclohexanedicarboxylic acid) (Cmax peak between 120 and 240 min).
This hydrolyzation occurs after 5 min (maximum plasma concentration), T1 / 2 <5 min.
In conclusion, the esults are not linear (high fluctuations between the animals and time points), which is why further studies are needed to generate trustworthy data.

Executive summary:

The study was conducted in 2 separate phases (i.e. 2 staggers) based on the

analytical results obtained for the first stagger. Bioanalytical data of the plasma

sample analysis of the first stagger indicated that no test item was quantifiable in

plasma samples. Solubility testing at LPT revealed that the test item was insoluble

in 0.9% NaCI solution used as vehicle. lnsolubility resulted in the formation of two

separate clear phases and only 0.9% NaCI solution was presumably administered.

No formulation analysis was carried out and phase separation could not be

detected visually prior to administration.

Testing of various solvents (data not included in this report) confirmed

5% Tween 80® in 0.9% NaCI solution as the most suitable vehicle for

administration of DINCD with respect to solubility and tolerability in the given

animal model.

An additional stagger (stagger 2) was employed administered with the test item

using Tween 80® in 0.9% NaCI solution as vehicle. Bioanalytical data revealed

high data variability for both DINCD and CHDCA (DINCD metabolite) plasma levels.

The maximum DINCD in plasma concentrations determined 5 minutes post

administration (p.a.) ranged from 2727.73 to 4229.63 ng/ml (3380.52

± 769.95 ng/ml) for animal nos. 9 to 11.

The metabolite CHDCA was also detected and quantified in the plasma of all

animals treated once intravenously with 100 mg DINCD/kg b.w. Metabolite plasma

concentrations increased steadily with a peak value determined between 80 and

160 minutes p.a. (80 minutes p.a.: 540.22 ± 416.85 ng/ml; 160 minutes p.a.:

327.54 ±16.41 ng/ml).

Furthermore, formulation analysis revealed a high variance in sample recovery of

only a 60 to 84% recovery with respect to the test item concentration.

Due to the observed difficulties regarding solubility and stability of the test item

DINCD in various solvents, as well as to generate more reliable data, further

solubility testing are recommended associated with formulation analyses prior to

administration.