Alcohols, C8-14, γ-ω-perfluoro

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2000

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Well documented GLP compliant study.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2000

Report date:

2001

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

The objective of this study was to evaluate the potential for FC 210 (H-24541), when administered by gavage, to be absorbed and to bioaccumulate in a mammalian system, as indicated by analytical determination of total fluorine in blood and liver. The test substance was compared to 2 positive controls that were materials previously shown to bioaccumulate in mammals. All blood samples were analyzed for total fluorine content. This report contains the results of those analyses

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

Fluoroalkylethanol mixture

IUPAC Name:

Fluoroalkylethanol mixture

Constituent 2

Reference substance name:

Alcohols, C8-14, γ-ω-perfluoro

EC Number:

269-927-8

EC Name:

Alcohols, C8-14, γ-ω-perfluoro

Cas Number:

68391-08-2

Molecular formula:

C8H5F13O - C14H5F25O

IUPAC Name:

3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctan-1-ol; 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecan-1-ol; 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-henicosafluorododecan-1-ol; 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13,14,14,14-pentacosafluorotetradecan-1-ol

Test material form:

other: solid, light brown

Details on test material:

Test substance: Fluowet EA 812
Code/synonyms: FC 210, H-24541
Content active substance in product:
98% (Perfluorooctyl ethanol 55 %, Perfluorodecyl ethanol 25 %, Perfluorododecyl ethanol 12 %, others 6 %)
Content of fluorine in active substance: 70 %

Radiolabelling:

no

Test animals

Species:

rat

Strain:

other: Crl:CD®(SD)IGS BR

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: rats were received from Charles River Laboratories, Inc., Raleigh, North Carolina.
- Age at study initiation: not reported
- Weight at study initiation: not reported
- Fasting period before study: not reported
- Housing:
- singly in stainless steel, wire-mesh cages suspended above cage boards.
- Individual metabolism cages: yes
- Diet (e.g. ad libitum): certified rodent chow (PMI Nutrition International, Inc. Certified Rodent LabDiet® 5002 chow) ad libitum
- Water: ad libitum
- Acclimation period: Upon arrival, the rats were removed from shipping cartons and quarantined for 6 days. The rats were weighed 3 times during the pretest period and examined daily for any clinically apparent signs of disease or injury. The rats were observed daily for mortality and signs of illness, injury, or abnormal behavior. On the bases of acceptable body weight gains and freedom from clinically apparent signs of disease or injury, the rats were released from quarantine by the laboratory animal veterinarian.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 23 ± 1°C
- Humidity (%): 50 ± 10%
- Air changes (per hr): not reported
- Photoperiod: 12-hour light/dark cycle (fluorescent light)

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

other: 0.5% aqueous methylcellulose

Details on exposure:

PREPARATION OF DOSING SOLUTIONS:
The test substance was a solid. According to sponsors instruction H-24541 was heated in a 80°C waterbath until it became a clear liquid and then stirred for at least 10 minutes until homogenous. The test substance was then aliquoted into 10 containers. On each day of dosing, one container was similarly heated and stirred. The liquefied test substance was suspended in 0.5% aqueous methylcellulose.
Rats were exposed by oral gavage to 1000 mg/kg/day of H-24541 suspended in 0.5% aqueous methylcellulose. The rats were dosed at a volume of 1 mL/100 g of body weight. The dosing suspensions were stirred on a magnetic stir plate throughout the dosing procedure to maintain homogeneity.

Duration and frequency of treatment / exposure:

The test substance was administered to 1 group of 5 rats for 5 consecutive days and to 5 groups for 10 days.

Doses / concentrations

Remarks:

Doses / Concentrations:
Limit dose: 1000 mg/kg/day of H-24541

No. of animals per sex per dose / concentration:

1 group of 5 male rats for 5 consecutive days
and 5 groups of 5 male rats each for 10 days.

Control animals:

yes, concurrent vehicle

Positive control reference chemical:

2 positive controls:
1) FC 100 (code H-24538, 20 mg/kg/day), i.e. a solution of PFOA (30 %) in water. The applied dose of 20 mg/kg/d of FC 100 corresponds therefore to a dose of 7 mg/kg/d of PFOA
2) PFOS (code: H-24019, 10 mg/kg/day)
Positive controls:
H-24019 was suspended in 0.5% aqueous methylcellulose. H-24538 was mixed with deionized water so an accurate volume could be delivered. The amount each rat received was based on the body weight collected on each day of dosing and the suspension/mixture concentration. The rats were dosed at a volume of 1 mL/100 g of body weight. The dosing preparations were stirred on a magnetic stir plate throughout the dosing procedure to maintain homogeneity.
Negative controls:
A preparation of 0.5% aqueous methylcellulose was chosen as the negative control because it was the vehicle for H-24019, one of the positive controls. The rats were dosed at a volume of 1 mL/100 g of body weight. These rats were dosed in a separate room from the rats dosed with the test substance or positive controls.

Details on study design:

Groups of 5 male rats each were exposed to 1000 mg/kg/day of H-24541 in 0.5 % methylcellulose. The test substance was administered to 1 group for 5 consecutive days and to 5 groups for 10 days.
Approximately 2 hours after the first dose, blood was collected from the orbital sinus of each rat from the 5-dose group.
On selected days (5, 10, 13, 24, 52, 94) 5 rats per group were euthanized and the blood, livers, and fat were collected. Body weights and clinical signs were recorded on each day of dosing and then weekly during the recovery period.
Additionally, a negative control, 0.5% aqueous methylcellulose, and 2 positive controls, PFOS (H-24019, 10 mg/kg/day) and FC 100 (H-24538, 20 mg/kg/day), were tested as described for H-24541.
The daily dosage of 1000 mg/kg for the test substance was selected based on the results of a rangefinding study. In the rangefinding study, a group of 5 male rats was dosed by oral gavage for 5 consecutive days with H-24541 at a dosage of 1000 mg/kg. The rats had an overall weight gain of 28 grams. The dosage of 1000 mg/kg was selected for the limit dosage for this project.

Details on dosing and sampling:

Test substance:
Rats were exposed by oral gavage to 1000 mg/kg/day of H-24541 suspended in 0.5% aqueous methylcellulose. The rats were dosed at a volume of 1 mL/100 g of body weight. The dosing suspensions were stirred on a magnetic stir plate throughout the dosing procedure to maintain homogeneity.
Positive controls:
H-24019 was suspended in 0.5% aqueous methylcellulose.
H-24538 was mixed with deionized water so an accurate volume could be delivered. The amount each rat received was based on the body weight collected on each day of dosing and the suspension/mixture concentration. The rats were dosed at a volume of 1 mL/100 g of body weight. The dosing preparations were stirred on a magnetic stir plate throughout the dosing procedure to maintain homogeneity.
Negative controls:
A preparation of 0.5% aqueous methylcellulose was chosen as the negative control because it was the vehicle for H-24019, one of the positive controls. The rats were dosed at a volume of 1 mL/100 g of body weight. These rats were dosed in a separate room from the rats dosed with the test substance or positive controls.

PHARMACOKINETIC STUDY (Absorption, distribution, excretion)
- Tissues and body fluids sampled: blood, liver and fat
- Time and frequency of sampling: On test day 1 (2 hours post dosing) blood was collected from the orbital sinus of each of 5 rats. On selected days 5, 10, 13, 24, 52, 94, five rats per group were euthanized and the blood, livers, and fat were collected.
Only the test day 5, 10, and 94 livers and fat were analyzed for total fluorine. These time points provided sufficient data to determine the accumulation and persistence of fluorine in the liver and fat. The total fluorine content of the blood, liver, and fat samples was determined using a Wickbold torch combustion method, followed by analysis with a fluoride ion selective electrode.

Statistics:

Descriptive statistics (e.g. mean, standard deviation) were used.
Noncompartmental analysis was conducted on fluorine data derived from rats dosed with H-24541 and the positive controls using WinNonlin Version 3.1 software (Pharsight Corp, Mountain View, CA). WinNonlin software provided a means of computing derived pharmacokinetic parameters from experimental data. All analysis was calculated using the μM equivalent in blood, liver, and fat data.

Results and discussion

Preliminary studies:

See Details on study design

Toxicokinetic / pharmacokinetic studies

Details on absorption:

Absorption after oral application indicated by blood fluorine levels.

Details on distribution in tissues:

Liver weights
The mean relative liver weight of rats dosed with the test substance, H-24541, was 21% higher on day 10 than the liver weight of rats in the negative control group. The mean relative liver weights of rats dosed with H-24541 were 36 or 7% higher on days 13 and 24 (recovery) than the liver weights of rats in the negative control group. The weights were similar during the remainder of the recovery period.
Liver weights of rats dosed with the test substance, H-24541, were elevated at the end of the 10-day dosing period but were similar to the negative controls by day 52 of the recovery period. Relative liver weights by the end of recovery in rats dosed with test substance were lower than in rats dosed with one positive control (H-24019) but similar to those in rats treated with the other positive control, H-24538.

Fluorine levels:
Liver:
Levels of total fluorine in livers from rats dosed with the test substance, H-24541, were lower than the levels in livers from rats dosed with the positive control materials. The total fluorine concentration in the liver from rats treated with H-24541 was 27.15 μM equivalents at day 10 and 0.59 μM equivalents at day 94.
Fat:
Levels of total fluorine in fat from rats dosed with the test substance were lower on day 10 than the levels in fat from rats dosed with the positive control materials. The fluorine concentration in the fat from rats dosed with the test substance was 32.76 μM equivalents on day 10 and 7.25 μM equivalents on day 94.
During the dosing period, the concentrations of fluorine in the liver and fat from rats dosed with the test substance were approximately an order of magnitude higher than the levels in the blood. The concentration of fluorine in the liver was very low by day 94, but the fat concentration remained elevated.

Factors Influencing Interpretation of Analysis:
The data used in the kinetic analysis were derived from a limited screen, and therefore several caveats and considerations are important. A couple of considerations of particular importance are (1) a single dosage was used and kinetics may or may not be linear, (2) the kinetics apply only to blood, (3) steady-state may not have been achieved, and (4) the sample size is low and may impact calculation of the terminal half-life.

Metabolite characterisation studies

Metabolites identified:

no

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information): other: some retention of fluorine in fat at day 94
A steady-state for fluorine in the blood was not achieved during the 10-day dosing period with the test substance. Dose-adjusted areas under the curve (AUCINF/D) for positive controls, H-24019 and H-24538, were approximately 670x and 410x the AUCINF/D for the test substance.

Executive summary:

The objective of this study was to evaluate the potential for FC 210 (H-24541), when administered by gavage, to be absorbed and to bioaccumulate in a mammalian system, as indicated by analytical determination of total fluorine in blood and liver.

Rats dosed for 10 consecutive days with 1000 mg/kg H-24541 exhibited no mortality, test substance-related clinical signs, or body weight effects. Liver weights were elevated in rats dosed with the test substance. A steady-state for fluorine in the blood was not achieved during the 10-day dosing period with the test substance. Dose-adjusted areas under the curve (AUCINF/D) for positive controls, H-24019 and H-24538, were approximately 670x and 410x the AUCINF/D for the test substance.

Blood was sampled at seven time points throughout the study, with only four of them occurring post-dose. The small sample size and analytical variability should be taken into account when using the derived terminal half-life for comparative purposes.

Under the conditions of this study, there was minimal absorption and retention of fluorine in the blood following dosing with H-24541. Administration of the test substance, H-24541, to male rats for 10 consecutive days resulted in some absorption and retention in the liver and fat. However, fluorine levels in blood, liver, and fat in rats dosed with H-24541 were lower than the fluorine levels in rats dosed with the positive control materials, H-24019 and H-24538, except for the day 94 fat levels. Some fluorine remained in the fat from rats dosed with H-24541. Most of the fluorine levels on day 94 for the positive control materials were below the limit of quantification.