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Toxicological information

Basic toxicokinetics

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Administrative data

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

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2014
Report Date:
2014

Materials and methods

Objective of study:
absorption
toxicokinetics
Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 417 (Toxicokinetics)
Deviations:
no
Qualifier:
according to
Guideline:
EPA OTS 798.7485 (Metabolism and Pharmacokinetics)
Deviations:
no
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Details on test material:
Purity: 93.6%
Radiolabelling:
no

Test animals

Species:
rat
Strain:
other: Crl:CD(SD)
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Laboratories International, Inc., Raleigh, North Carolina, U.S.A.
- Age at study initiation: 9 - 11 weeks
- Weight at study initiation: 299 - 366 g
- Fasting period before study: Animals for the oral and intravenous administration experiments were fasted (approximately 18 ± 2 hours) before dosing with test substance. Animals for the repeat dose 14-day oral administration experiment were not fasted before dosing with the test substance. Food was returned approximately 2 hours post dose.
- Housing: During the pretest period, animals were group housed (non-cannulated) or housed individually (cannulated) in solid bottom caging with Bed-O-Cob® and Nestlets. For the in-life phase, animals were housed individually in solid-bottom caging with Bed-O-Cob® and Nestlets.
- Diet: PMI® Nutrition International, LLC Certified Rodent LabDiet® 5002 ad libitum, except when fasted
- Water: tap water ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 - 26ºC
- Humidity (%): 30 - 70%
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:
other: single oral gavage, intravenous, or 14-day repeated oral gavage
Vehicle:
other: oral gavage doses were prepared with 0.1% Tween 80 with 0.5% methylcellulose; intravenous dose was prepared with 10% dimethyl sulfoxide, 10% glycerol formal, and 2.5% tween 80 in 40% hydroxypropyl-β-cyclodextrine solution
Details on exposure:
PREPARATION OF TEST SUBSTANCE FORMULATION:

- Solvent used:
Oral Gavage doses were prepared with 0.1% Tween 80 in 0.5% methylcellulose
Intravenous dose was prepared with 10% dimethyl sulfoxide, 10% glycerol formal, and 2.5% tween 80 in 40% hydroxypropyl-β-cyclodextrine solution
- Preparation frequency: once
- Preparation details: The test item was mixed with 0.5% methylcellulose with 0.1% Tween 80 for oral gavage administration or 10% dimethyl sulfoxide, 10% glycerol formal, and 2.5% tween 80 in 40% hydroxypropyl-β-cyclodextrine solution for intravenous administration. The formulation for oral administration was a homogenous suspension and the intravenous formulation was visibly observed to be a clear solution. Furthermore, the intravenous dose was sterile filtered through a 0.22 μm filter.
- Adjusted for purity: no
Duration and frequency of treatment / exposure:
Single oral gavage administration
14-day repeated oral gavage administration
Single intravenous administration
Doses / concentrations
Remarks:
Doses / Concentrations:
Single oral gavage: 50 (Group 1) or 1000 mg/kg bw (Group 2)
14-day repeated oral gavage: 50 mg/kg bw (Group 4)
Single intravenous: 5 mg/kg bw (Group 3)
No. of animals per sex per dose:
4 per dose level
Control animals:
no
Details on study design:
- Dose selection rationale: The high dose was set at 1000 mg/kg bw, which is the maximum dose recommended per OECD Guideline 417. The low dose was set at 50 mg/kg bw, which was selected to bracket the two lowest doses in the 2-week dose range-finding toxicity study by oral gavage in rats. For the intravenous administration experiment, a dose of 5 mg/kg bw was chosen, which is 1/10 of the low dose for the single dose oral gavage experiment. For the repeated dose 14-day oral gavage experiment, the dose was set to 50 mg/kg bw, which is equal to the low dose for the single oral gavage experiment.
Details on dosing and sampling:
PHARMACOKINETIC STUDY (Absorption, distribution, excretion)
- Tissues and body fluids sampled: blood from tail vein
- Time and frequency of sampling:
Oral gavage: 0, 15 and 30 min, as well as at 1, 2, 4, 8, 12, 24, 48, 72, 96, 120, 144, and 168 hours
Intravenous administration: 0, 2, 5, 15, and 30 min, as well as at 1, 2, 6, 12, 24, 48, 72, 96, 120, 144, and 168 hours
- Other: Blood was processed into plasma, which was stored frozen at ≤-10°C until it was analysed
- From how many animals: samples pooled across the 4 animals
- Method type(s) for identification: HPLC-MS
- Limits of detection and quantification: The LOD and LOQ for the test item were 0.75 and 2.5 ng/mL, respectively.
Statistics:
Group data were represented as a mean ± SD as appropriate. Tables and appendices presented in the report were computer generated and values were rounded appropriately for inclusion in the report. Consequently, the application of manual calculation to report values may have, in some instances, yielded a minor variation. These occurrences should not be construed as adversely affecting the integrity or interpretation of the data.

Results and discussion

Toxicokinetic / pharmacokinetic studies

Details on absorption:
In summary, the pharmacokinetics of the test item showed that 1) it was rapidly absorbed and eliminated; 2) bioavailability decreased from 30.2% to 5.58%, indicating a saturation in absorption as the dose increased from 50 mg/kg bw to 1000 mg/kg bw; and 3) it did not accumulate following 14-day repeated oral gavage dosing.
Toxicokinetic parametersopen allclose all
Test no.:
#1
Toxicokinetic parameters:
Cmax: 5660 (±1490) ng/mL single low dose oral
Test no.:
#2
Toxicokinetic parameters:
Cmax: 11500 (±1500) ng/mL single high dose oral
Test no.:
#1
Toxicokinetic parameters:
Tmax: 0.5 (±0.0) hours single low dose oral
Test no.:
#2
Toxicokinetic parameters:
Tmax: 0.88 (±0.25) hours single high dose oral
Test no.:
#1
Toxicokinetic parameters:
AUC: 10400 (±1900) hr x ng/mL single low dose oral
Test no.:
#2
Toxicokinetic parameters:
AUC: 38400 (±7200) hr x ng/mL single high dose oral
Test no.:
#1
Toxicokinetic parameters:
half-life 1st: 2.0 (±0.4)hours single low dose oral
Test no.:
#2
Toxicokinetic parameters:
half-life 1st: 5.6 (±1.8) hours single high dose oral
Test no.:
#3
Toxicokinetic parameters:
Cmax: 6140 (±670) ng/mL intravenous administration
Test no.:
#3
Toxicokinetic parameters:
Tmax: 0.046 (±0.025) hours intravenous administration
Test no.:
#3
Toxicokinetic parameters:
AUC: 3430 (±300) hr x ng/mL intravenous administration
Test no.:
#3
Toxicokinetic parameters:
half-life 1st: 2.0 (±0.7) hours intravenous administration
Test no.:
#4
Toxicokinetic parameters:
Cmax: 6080 (±1580) ng/mL 14-day repeated dose oral gavage
Test no.:
#4
Toxicokinetic parameters:
Tmax: 0.51 (±0.02) hours 14-day repeated dose oral gavage
Test no.:
#4
Toxicokinetic parameters:
AUC: 10100 (±2200) hr x ng/mL 14-day repeated dose oral gavage
Test no.:
#4
Toxicokinetic parameters:
half-life 1st: 4.0 (±2.0) hours 14-day repeated dose oral gavage

Metabolite characterisation studies

Metabolites identified:
no

Any other information on results incl. tables

Based on the dose administration data, all animals received the targeted dose for each treatment group. There were no clinical signs observed in any test group.

For the intravenous administration experiment, mean peak plasma concentration (Cmax) was 6140 (±670) ng/mL and the Tmax value was observed at 0.046 (±0.025) hours. The mean terminal elimination half-life (T1/2) value was 2.0 (±0.7) hours with an area-under-the-curve (AUC) value of 3430 (±300) hr x ng/mL. The volume of distribution (V) and clearance (CL) values were 4270 (±1610) mL/kg and 1460 (±140) mL/hour/kg.

For the single dose oral gavage experiment, Cmax at the low and high dose were 5660 (±1490) and 11500 (±1500) ng/mL, respectively. Absorption was rapid with mean Tmax values of 0.50 (±0.0) and 0.88 (±0.25) hours at the low and high dose, respectively. The T1/2 values were 2.0 (±0.4) and 5.6 (±1.8) hours at the low and high dose, respectively. The AUC for the low and high dose were 10,400 (±1900) and 38400 (±7200) hr x ng/mL, respectively. Oral bioavailability decreased from 30.2 (±6.2) % to 5.58 (±1.15) % as the dose increased from 50 mg/kg bw to 1000 mg/kg bw, indicating a saturation in absorption.

For the 14-day repeated dose oral gavage experiment, the Cmax and Tmax values were 6,080 (±1580) ng/mL and 0.51 (±0.02) hours, respectively. Elimination was rapid with a T1/2 value of 4.0 (±2.0) hours. The AUC value was 10100 (±2200) hr x ng/mL, which is slightly less than 10400 (±1,900) hr x ng/mL, the value obtained after the single oral gavage dose. This indicates that the test item did not accumulate following 14-day repeated oral gavage dosing.

Applicant's summary and conclusion

Conclusions:
Not likely to accumulate following multiple dosing.
The pharmacokinetics of the test item showed that it was rapidly absorbed and eliminated. Bioavailability of the test item decreased from 30.2% to 5.58%, indicating a saturation in absorption as the dose increased from 50 mg/kg bw to 1000 mg/kg bw. The test item did not accumulate following 14-day repeated oral gavage dosing.
Executive summary:

The toxicokinetics of the test item was studied in male Sprague-Dawley rats. Experiments were performed to understand plasma kinetics following single oral gavage, intravenous, or 14-day repeated oral gavage administration. Four male rats were administered the test item at 50 or 1000 mg/kg bw by single oral gavage. Another four male rats were administered the test item at 50 mg/kg bw daily by gavage for 14 days. Following the last administered dose, blood was collected via the tail vein at 15 and 30 min, as well as at 1, 2, 4, 8, 12, 24, 48, 72, 96, 120, 144, and 168 hours.

Based on the dose administration data, all animals received the targeted dose for each treatment group. There were no clinical signs observed in any tested group.

For the intravenous administration experiment, mean peak plasma concentration (Cmax) was 6,140 (±670) ng/mL and the Tmax value was observed at 0.046 (±0.025) hours. The mean terminal elimination half-life (T1/2) value was 2.0 (±0.7) hours with an area-under-the-curve (AUC) value of 3,430 (±300) hr x ng/mL. The volume of distribution (V) and clearance (CL) values were 4,270 (±1,610) mL/kg and 1,460 (±140) mL/hour/kg.

For the single dose oral gavage experiment, Cmax at the low and high dose were 5660 (±1490) and 11500 (±1500) ng/mL, respectively. Absorption was rapid with mean Tmax values of 0.50 (±0.0) and 0.88 (±0.25) hours at the low and high dose, respectively. The T1/2 values were 2.0 (±0.4) and 5.6 (±1.8) hours at the low and high dose, respectively. The AUC for the low and high dose were 10400 (±1900) and 38400 (±7200) hr x ng/mL, respectively. Oral bioavailability decreased from 30.2 (±6.2) % to 5.58 (±1.15) % as the dose increased from 50 mg/kg bw to 1000 mg/kg bw, indicating a saturation in absorption.

For the 14-day repeated dose oral gavage experiment, the Cmax and Tmax values were 6080 (±1580) ng/mL and 0.51 (±0.02) hours, respectively. Elimination was rapid with a T1/2 value of 4.0 (±2.0) hours. The AUC value was 10100 (±2200) hr x ng/mL, which is slightly less than 10400 (±1900) hr x ng/mL, the value obtained after the single oral gavage dose. This indicates that the test item did not accumulate following 14-day repeated oral gavage dosing.

In summary, the pharmacokinetics of the test item showed that 1) it was rapidly absorbed and eliminated; 2) bioavailability of the test item decreased from 30.2% to 5.58%, indicating a saturation in absorption as the dose increased from 50 mg/kg bw to 1000 mg/kg bw; and 3) it did not accumulate following 14-day repeated oral gavage dosing.