reaction mass of 5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-2H -isothiazol-3-one

Basic toxicokinetics

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:

2005

Report date:

2005

Materials and methods

Objective of study:

absorption

distribution

excretion

metabolism

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 417 (Toxicokinetics)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OTS 798.7485 (Metabolism and Pharmacokinetics)

Deviations:

no

GLP compliance:

yes

Test material

Test material information

Constituent 1

Test material form:

other: Amber Liquid

Details on test material:

- Name of test material (as cited in study report): Kathon™ 886
- Physical state: Amber liquid
- Stability under test conditions: stable at room temperature

Specific details on test material used for the study:

SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: Rohm and Haas, Batch No. 1018.0012 (14C-CMIT), 8001J123 (12C-MIT) and 0000371525 (non-labeled Kathon™ 886F)

RADIOLABELLING INFORMATION (if applicable)
- Radiochemical purity: 99.9%
- Specific activity: 51.65 mCi/g
- Locations of the label: 14C 4,5

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: Radiolabeled material was stored at ca. -20°C in a tightly closed container. Non-radiolabeled material was stored in a refrigerator.
- Stability under test conditions: Stable
- Solubility and stability of the test substance in the solvent/vehicle: Soluble and stable
- Reactivity of the test substance with the solvent/vehicle of the cell culture medium: Not applicable

TREATMENT OF TEST MATERIAL PRIOR TO TESTING
- Treatment of test material prior to testing: Dissolution in water
- Preliminary purification step (if any): No
- Final dilution of a dissolved solid, stock liquid or gel: 0.5, 1.5 and 3 mg/mL

FORM AS APPLIED IN THE TEST (if different from that of starting material)
Liquid

OTHER SPECIFICS: Purity of non-labeled test material was 51.4% (Batch No. 8001J123) and 14.11%, of which 10.45% CMIT and 3.66% MIT (Batch No. 0000371525). Test substance was equivalent to Kathon™ 886F with 14C-labelled CMIT.

Radiolabelling:

yes

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Hilltop Lab Animals, Inc. (Scottsdale, Pennsylvania, USA)
- Age at study initiation: 8-10 weeks old
- Weight at study initiation: 232-265 g
- Housing: Stainless steel metabolic cages
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: ca. 24 h

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-25 °C
- Humidity (%): 50 +/- 20 %
- Air changes (per hr): Not reported
- Photoperiod (hrs dark / hrs light): 12h/12h

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

water

Duration and frequency of treatment / exposure:

Single dose and 96 h of exposure

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

3.75 mg/kg bw (total dose)

Remarks:

Low dose, males/females

Doses / concentrations 2

Dose / conc.:

11.25 mg/kg bw (total dose)

Remarks:

High dose, females

Doses / concentrations 3

Dose / conc.:

22.5 mg/kg bw (total dose)

Remarks:

High dose, males

No. of animals per sex per dose / concentration:

4

Control animals:

yes

Details on dosing and sampling:

TOXICOKINETIC / PHARMACOKINETIC STUDY (Absorption, distribution, excretion)
- Tissues and body fluids sampled (delete / add / specify): urine, faeces and selected tissues: whole blood, plasma, liver, fat, kidneys, bone marrow (femur bone), heart, lungs, brain, testes (male), ovaries (female), muscle (hind leg), spleen, adrenals, thyroids and remaining carcass.
- Time and frequency of sampling: Rats were killed at 96 h post-dose. Urine, cage rinse, and faeces were collected from rats at 24 h intervals for a total of 96 hours. Selected tissues were collected fom all animals in all groups.

METABOLITE CHARACTERISATION STUDIES
- Tissues and body fluids sampled (delete / add / specify): urine, faeces, cage rinse
- Time and frequency of sampling: Every 24 h up to 96 h
- From how many animals: all animals
- Method type(s) for identification: HPLC-UV, Liquid scintillation counting

Results and discussion

Main ADME results

Main ADME results 1

Type:

excretion

Results:

14C-CMIT-derived 14C-label was rapidly and extensively excreted in the urine and faeces following oral administration

Main ADME results 2

Type:

metabolism

Results:

14C-CMIT-derived 14C-label is extensively metabolized

Main ADME results 3

Type:

distribution

Results:

Tissues contained 0.93-1.44% (female and male, respectively) of dosed radioactivity in the low dose group and 3.94-4.72% (female and male, respectively) in the high dose group.

Toxicokinetic / pharmacokinetic studies

Details on distribution in tissues:

Tissues contained 0.93-1.44% (female and male, respectively) of dosed radioactivity in the low dose group and 3.94-4.72% (female and male, respectively) in the high dose group. The highest amount of radioactivity was found in blood, particularly in red blood cells (0.67-1.09% of the dose in the low dose group, and 3.41-4.11% in the high dose group), followed by muscle (0.15%) in low dose group, and by muscle and liver (0.25%) in high dose group.

Details on excretion:

14C-CMIT-derived 14C-label was rapidly and extensively excreted in the urine and faeces following oral administration. A majority of the radioactivity was excreted from the rats in 24 hour (77-87%). Renal and fecal routes of elimination were equally important.

Metabolite characterisation studies

Metabolites identified:

yes

Details on metabolites:

14C-CMIT-derived 14C-label is extensively metabolized. Approximately twenty-nine radioactive components were observed in urine and faeces samples from the HPLC radioprofiling. Among these N-methyl malonamic acid was detected as the major component in the urine (15.35-18.19%). 3-mercapturic acid conjugate of 3-sulfinyl-N-methyl-propionamide was detected as the major component in the feces (up to 32.54%). All other metabolites accounted for less than 5% of the dose. Metabolites are thought to result from reduction and oxidation reactions involving phase I enzymes followed by conjugation to glutathione, giving rise to conjugates to glutathione or to mercapturic acid.

Applicant's summary and conclusion

Conclusions:

14C-CMIT-derived 14C-label was rapidly and extensively excreted in the urine and faeces following oral administration. A majority of the radioactivity was excreted from the rats in 24 hour (77-87%). Renal and fecal routes of elimination were equally important. Tissues contained 0.93-1.44% of dosed radioactivity in the low dose group and 3.94-4.72% in the high dose group. Total mean recovery of radioactivity ranged from 85.73 - 95.60%. Gender differences in excretion appeared to be minimal.

Executive summary:

This study fulfills the requirements for an OECD 417 and OPPTS 870.7485 Toxicokinetic study. There were no guideline deviations. 14C-CMIT-derived 14C-label was rapidly and extensively excreted in the urine and faeces following oral administration. A majority of the radioactivity was excreted from the rats in 24 hour (77-87%). Renal and fecal routes of elimination were equally important. Tissues contained 0.93-1.44% (female and male, respectively) of dosed radioactivity in the low dose group and 3.94-4.72% (female and male, respectively) in the high dose group. The highest amount of radioactivity was found in blood, particularly in red blood cells (0.67-1.09% of the dose in the low dose group, and 3.41-4.11% in the high dose group), followed by muscle (0.15%) in low dose group, and by muscle and liver (0.25%) in high dose group. Total mean recovery of radioactivity ranged from 85.73 - 95.60%. Gender differences in excretion appeared to be minimal. 14C-CMIT-derived14C-labelis extensively metabolized.Approximately twenty-nine radioactive components were observed in urine and faeces samples from the HPLC radioprofiling. Among these N-methyl malonamic acid was detected as the major component in the urine (15.35-18.19%). 3 -mercapturic acid conjugate of 3 -sulfinyl-N-methyl-propionamide was detected as the major component in the feces (up to 32.54%). All other metabolites accounted for less than 5% of the dose. Metabolites are thought to result from reduction and oxidation reactions involving phase I enzymes followed by conjugation to glutathione,giving rise to conjugates to glutathione or to mercapturic acid.