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Reference
Endpoint:
basic toxicokinetics in vivo
Type of information:
experimental study
Adequacy of study:
key study
Study period:
23 March 2017 - 3 April 2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Objective of study:
absorption
distribution
excretion
toxicokinetics
Qualifier:
according to
Guideline:
OECD Guideline 417 (Toxicokinetics)
Version / remarks:
Not specified in the study report
Deviations:
no
Qualifier:
according to
Guideline:
other: Commission Regulation (EC) No 440/2008 laying down test methods pursuant to Regulation (EC) No 1907/2006 (REACH), Part B: Methods for the determination of toxicity and other health effects: Toxicokinetics; Official Journal of the European Union, No. L 142
Version / remarks:
30 May 2008
Deviations:
no
GLP compliance:
yes
Specific details on test material used for the study:
RADIOLABELLING INFORMATION (if applicable)
- Radiochemical purity: 99.4%
- Batch: CFQ43033
- Specific activity: 2.11 GBq/mmol
- Locations of the label: N,N-dimethyl-D-[1-(14C)]glucamine
- Expiration date of radiochemical substance: not specified

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: non-radiolabelled: at room temperature protected from light; radiolabelled: in ultra-low freezer (≤ -75°C)
- Stability under test conditions: stable
- Solubility and stability of the test substance in the solvent/vehicle: soluble in water; stable.

OTHER SPECIFICS:
- Correction factor for purity was applied (0.712 based on active ingredient).
- Specific gravity/density: ~ 1.21 g/cm3
- pH 10.9 at concentration 10 g/L (at 25°C)
Radiolabelling:
yes
Remarks:
14C
Species:
rat
Strain:
Sprague-Dawley
Remarks:
Crl: OFA
Details on species / strain selection:
The Sprague-Dawley rat was chosen as the animal model for this study as it was used in earlier toxicity tests.
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Laboratories France, L'Arbresle Cedex, France
- Age at study initiation: 7 weeks
- Weight at study initiation: 226-237 g (non-cannulated); 244-470 g (bile-cannulated)
- Housing:
Upon arrival: group-housed (up to 4/cage) in polycarbonate Makrolon cages with sawdust as bedding material.
During the study:
Mass-balance group (Group 1): individually in stanless steel metabolism cages with a grid and Plexiglas lid, with 4 glass gas absorption towers.
Kinetic group (Group 2): individually in polycarbonate Makrolon cages with a bottom grid and paper bedding.
Bile-cannulated animals (Group 3): stainless steel metabolism cages with a grid, attached to the bile collection system, with replacement fluid infusion (sodium cholate and sodium bicarbonate) at a rate of 0.9-1.25 mL/hour.
Paper was provided as enrichment, except during the study procedures/activities. Two days after dosing animals in Group 1 were provided with a crawlball in the metabolism cage, except when interrupted by study procedures/activities.
- Diet: pelleted rodent diet (SM R/M-Z from SSNIFF® Spezialdiäten GmbH, Soest, Germany), ad libitum, except during designated procedures. The rats were deprived of food for approximately 18 h prior to and for approximately four hours after dose administration, except for the bile cannulated animals (Group 3) which received food ad libitum.
- Water: municipal water in water bottles, ad libitum
- Acclimation period: at least 5 days, except for the bile-cannulated animals, which were used as soon as possible after delivery

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20.2-20.5
- Humidity (%): 44-48
- Air changes (per hr): ca.10
- Photoperiod (hrs dark / hrs light): 12.12

IN-LIFE DATES:
Non-cannulated: From: 23 March 2017 To: 3 April 2017
Cannulated: From: 30 Match 2017 To: 3 April 2017
Route of administration:
oral: gavage
Vehicle:
water
Details on exposure:
PREPARATION OF DOSING SOLUTIONS:
The radiolabeled formulation was prepared once for each group. A weighed amount of labeled 14C-Dimethylglucamine was placed in a glass container and the solvent evaporated by a gentle stream of nitrogen. Unlabeled Dimethylglucamine was added to achieve the specific activity of 1MBq/mg. Vehicle was added to obtain the desired concentration of 10 mg/mL. All radiolabeled formulations were prepared immediately prior to dosing and stored at ambient temperature, for a maximum of 5 hours. Before and during the treatment procedure the formulations were kept on a magnetic stirring device.
Duration and frequency of treatment / exposure:
Single oral gavage dose
Dose / conc.:
100 mg/kg bw/day (actual dose received)
Remarks:
corresponding to 10 MBq/kg bw
No. of animals per sex per dose:
Group 1: 4 males
Group 2: 8 males
Group 3: 4 males
Control animals:
no
Positive control:
Not applicable
Details on study design:
- Dose selection rationale:
The dose level, carrier and administration route was chosen in analogy to already performed toxicity tests in the same species

- Rationale for animal assignment:
Group 1 (conventional rats) and Group 3 (bile-cannulated rats) were used to define the absorption, distribution and excretion of labeled Dimethylglucamine. A total 14C-radioactivity material balance was determined for these groups.
Group 2 was used to determine the toxicokinetics of total 14C radioactivity.
Details on dosing and sampling:
TOXICOKINETIC / PHARMACOKINETIC STUDY (Absorption, distribution, excretion)
- Tissues and body fluids sampled: urine (Groups 1 and 3), faeces (Groups 1 and 3), volatiles (Group 1), blood and plasma (Group 2), cage washes (Groups 1 and 3), bile (Group 3), GI tract including contents (Groups 1 and 3 only), remaining carcass including blood (Groups 1 and 3 only).
- Time and frequency of sampling:
Urine:
Group 1: for the periods of 0-6, 6-24 h and then at 24 intervals to 72 h post-dose
Group 3: for the periods of 0-6, 6-24 h and then at 24 intervals to 96 h post-dose
Faeces:
Group 1: at 24 h intervals to 72 h post-dose
Group 3: at 24 h intervals to 96 h post-dose
Bile:
Group 3: for the periods of 0-6, 6-24 h and then at 24 intervals to 96 h post-dose
Volatiles:
Group 1: at 24 h intervals to 48 h post-dose
Cages washes:
Groups 1 and 3: at termination, the interior of the metabolism cages was rinsed with methanol/water (1:1, v/v).
Blood:
Group 2: at 30 min, 1,2, 4, 8, 24 and 74 h after dosing from 4 animals per time; collected from the jugular vein
GI tract and carcass (Groups 1 and 3): at termination.
Termination was performed at 72 h post-dosing for Groups 1 and 2 and at 96 h post-dosing for Group 3. No necropsy was performed for group 2.

Other observations:
Mortality/moribundity check: twice daily, in the morning and at the end of the working day, in cages
Clinical observations: at least once daily
Body weights: individually on the day of treatment
Food and water consumption: subjective appraisal was maintained during the study, but no quantitative investigation was introduced as no treatment related effect was suspected
Statistics:
Not performed.
Preliminary studies:
Not performed.
Type:
absorption
Results:
5.28% in conventional rats (Group 1) and 13.3% in bile-cannulated rats (Group 3)
Type:
excretion
Results:
99.0% total excretion after 72 hours in conventional rats (Group 1); 94.8% total excretion after 96 hours in bile-cannulated rats (Group 3).
Type:
distribution
Results:
0.276% in GI tract and carcass+ tissues in conventional rats (Group 1); 0.284% in GI tract and carcass plus tissues in bile-cannulated rats (Group 3)
Details on absorption:
The oral absorption of 14C-Dimethylglucamine related radioactivity was calculated by accumulating urine, volatiles (when applicable), bile (when applicable) and carcass recoveries after oral administration. The oral absorption was 5.28% in conventional rats (Group 1) and 13.3% in bile-cannulated rats (Group 3).
Details on distribution in tissues:
The average total remaining radioactivity in GI Tract and carcass plus tissues after 72 hours in conventional rats (Group 1) was 0.276% of the administered dose. In bile cannulated rats (Group 3) the average total remaining radioactivity in GI Tract and carcass plus tissues was 0.284% of the administered dose after 96 hours.
No further examination of the substance distribution in tissues was performed.
Details on excretion:
Urinary excretion: after oral administration of 100 mg/kg Dimethylglucamine in conventional rats (Group 1) urinary excretion of radioactivity was on average 4.80% of the administered dose after 72 hours. In bile cannulated rats (Group 3) urinary excretion of radioactivity was on average 12.9% of the administered dose after 96 hours. In both groups the majority of the radioactivity was excreted over the first 48 hours (~4.6% in Group 1 and ~12.4% in Group 3) and diminished rapidly thereafter.
Urinary excretion appeared a minor process in the elimination of the drug after oral administration.
Fecal excretion: sfter oral administration of 100 mg/kg Dimethylglucamine in conventional rats (Group 1) fecal excretion of radioactivity was on average 93.8% of the administered dose after 72 hours. In the bile cannulated rats (Group 3) fecal excretion of radioactivity was on average 81.2% of the administered dose after 96 hours. In both groups the majority of the radioactivity was excreted over the first 24 hours (~90.7% in Group 1 and ~70.2% in Group 3) and diminished rapidly thereafter.
Fecal excretion appeared the major route of elimination of the drug after oral administration.
Bile excretion: after oral administration of 100 mg/kg Dimethylglucamine bile excretion of radioactivity was on average 0.104% of the administered dose after 96 hours (bile-cannulated rats). Bile excretion appeared to be a negligible route of elimination of the drug after oral administration.
Bile excretion appeared to be a negligible route of elimination of the drug after oral administration.
Volatiles: the excretion of radioactivity in volatiles up to 48 hours after dosing (on average 0.218%) was negligible.


Key result
Toxicokinetic parameters:
Tmax: 0.5 h in blood and plasma
Key result
Toxicokinetic parameters:
Cmax: 1390 ng/g in blood and 2560 ng/g in plasma
Key result
Toxicokinetic parameters:
other: Elimination half-life 2.7 hours

Study design:

16 rats were divided into three groups and treated at dose of 100 mg/kg bw by a single oral gavage:

Groups

No. of rats

Time of sacrifice

Mass-balance conventional

4

72h

Mass-balance bile-cannulated

4

96h

Toxicokinetics

8

72h

 

In the mass-balance groups, urine was collected in 0-6, 6-24, 24-48 and 48-72 hours intervals.

Feces were collected in 0-24, 24-48 and 48-72 hours intervals. In the bile cannulated groups urine and feces was also collected from 72-96 hours. Animals were euthanized at the end of the collection period and cage washings were collected. The carcass was stored for total14C analysis. Total radioactivity in urine, feces, cage washings, tissues and organs was determined.

 

In the toxicokinetic groups, blood was sampled alternately from four rats per time point at 0.5, 1, 2, 4, 8, 24, 48 and 72 hour after dosing and examined for the radioactivity.

 

Results obtained for Mass-balance:

The majority of the radioactivity was excreted via feces, i.e. 94% in conventional rats after 72 hours and 81% after 96 hours in bile-cannulated rats. Urinary excretion accounted for 4.8% after 72 hours in conventional rats and 12.9% after 96 hours in bile cannulated rats. Excretion of radioactivity in bile up to 96 hours after dosing (0.1%) was negligible. These results indicate that the radioactivity excreted in the feces after oral administration consist of unabsorbed compound. Excretion of radioactivity in volatiles in conventional rats up to 48 hours after dosing (0.2%) was negligible.

At termination of the study, the average total remaining radioactivity in blood, carcass plus tissues was on average 0.3% in conventional rats (72 hours) and bile-cannulated rats (96

hours), indicating no accumulation of radioactivity.

Average total recovery of radioactivity after a single oral administration was 99.3% in

conventional rats and 95.1% in bile-cannulated rats.

The calculated oral absorption (accumulate urine, volatiles, bile and carcass recoveries) was on average 5% in conventional rats and 13% in bile-cannulated rats. The difference in oral absorption could be caused by the difference in test system, conventional versus bile-cannulated rats or that the conventional rats were deprived of food before dosing while bile-cannulated rats were not.

 

Results obtained for Toxicokinetics

The plasma concentration increased rapidly. The peak plasma concentration, Cmax, was reached at 0.5 hours after dosing. Total radioactivity measured in the whole blood following a single oral administration was lower than in plasma whatever the sampling time, indicating that there is no specific affinity to red blood cells. After absorption, the plasma radioactivity decreased rapidly with an apparent terminal half-life in plasma of 2.7 hours.

 

In conclusion, the orally applied N,N-Dimethyl-D-[1-14C]-Glucamine in rats was barely absorbed, and mainly excreted via the feces. The systemically available total radioactivity ranged 5-13%, which was excreted via urine. The plasma radioactivity decreased with an half-life of 2.7 hours.

Conclusions:
The toxicokinetic profile of the registration substance was investigated according to the Guideline OECD 417. The rats were treated with the radioactive labelled registration susbtance at dose of 100 mg/kg bw. It was barely absorbed, the total absorbed amoung being 5-10 % of applied dose. The absorbed radioactivity was eliminated via urinary route with the half-life in plasma of 2.7 hours. A low bioavailabiity, an efficient elimination and no bioaccumulating property could be demonstrated in this study.
Executive summary:

The toxicokinetic profile of the registration substance was investigated according to the Guideline OECD 417. The rats were treated with the radioactive labelled registration susbtance at dose of 100 mg/kg bw.

Study design:

16 rats were divided into three groups and treated at dose of 100 mg/kg bw by a single oral gavage:

Groups

No. of rats

Time of sacrifice

Mass-balance conventional

4

72h

Mass-balance bile-cannulated

4

96h

Toxicokinetics

8

72h

 

In the mass-balance groups, urine was collected in 0-6, 6-24, 24-48 and 48-72 hours intervals.

Feces were collected in 0-24, 24-48 and 48-72 hours intervals. In the bile cannulated groups urine and feces was also collected from 72-96 hours. Animals were euthanized at the end of the collection period and cage washings were collected. The carcass was stored for total14C analysis. Total radioactivity in urine, feces, cage washings, tissues and organs was determined.

 

In the toxicokinetic groups, blood was sampled alternately from four rats per time point at 0.5, 1, 2, 4, 8, 24, 48 and 72 hour after dosing and examined for the radioactivity.

 

Results obtained for Mass-balance:

The majority of the radioactivity was excreted via feces, i.e. 94% in conventional rats after 72 hours and 81% after 96 hours in bile-cannulated rats. Urinary excretion accounted for 4.8% after 72 hours in conventional rats and 12.9% after 96 hours in bile cannulated rats. Excretion of radioactivity in bile up to 96 hours after dosing (0.1%) was negligible. These results indicate that the radioactivity excreted in the feces after oral administration consist of unabsorbed compound. Excretion of radioactivity in volatiles in conventional rats up to 48 hours after dosing (0.2%) was negligible.

At termination of the study, the average total remaining radioactivity in blood, carcass plus tissues was on average 0.3% in conventional rats (72 hours) and bile-cannulated rats (96

hours), indicating no accumulation of radioactivity.

Average total recovery of radioactivity after a single oral administration was 99.3% in

conventional rats and 95.1% in bile-cannulated rats.

The calculated oral absorption (accumulate urine, volatiles, bile and carcass recoveries) was on average 5% in conventional rats and 13% in bile-cannulated rats. The difference in oral absorption could be caused by the difference in test system, conventional versus bile-cannulated rats or that the conventional rats were deprived of food before dosing while bile-cannulated rats were not.

 

Results obtained for Toxicokinetics

The plasma concentration increased rapidly. The peak plasma concentration, Cmax, was reached at 0.5 hours after dosing. Total radioactivity measured in the whole blood following a single oral administration was lower than in plasma whatever the sampling time, indicating that there is no specific affinity to red blood cells. After absorption, the plasma radioactivity decreased rapidly with an apparent terminal half-life in plasma of 2.7 hours.

 

In conclusion, the orally applied N,N-Dimethyl-D-[1-14C]-Glucamine in rats was barely absorbed, and mainly excreted via the feces. The systemically available total radioactivity ranged 5-13%, which was excreted via urine. The plasma radioactivity decreased with an half-life of 2.7 hours.

Description of key information

The toxicokinetic profile of the registration substance was investigated according to the Guideline OECD 417. The rats were treated with the radioactive labelled registration susbtance at dose of 100 mg/kg bw. It was barely absorbed, the total absorbed amoung being 5-10 % of applied dose. The absorbed radioactivity was eliminated via urinary route with the half-life in plasma of 2.7 hours. A low bioavailabiity, an efficient elimination and no bioaccumulating property could be demonstrated in this study.

Key value for chemical safety assessment

Bioaccumulation potential:
no bioaccumulation potential

Additional information