1-[[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]methyl]-1H-1,2,4-triazole

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

April 1987 to February 1988

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1989

Report date:

1989

Materials and methods

Objective of study:

absorption

distribution

excretion

metabolism

Test guideline

Qualifier:

according to guideline

Guideline:

EPA OPP 85-1 (Metabolism and Pharmacokinetics)

GLP compliance:

yes

Test material

Test material information

Constituent 1

Reference substance name:

1-[[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]methyl]-1H-1,2,4-triazole

EC Number:

262-104-4

EC Name:

1-[[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]methyl]-1H-1,2,4-triazole

Cas Number:

60207-90-1

Molecular formula:

C15H17Cl2N3O2

IUPAC Name:

1-{[2-(2,4-dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl]methyl}-1H-1,2,4-triazole

Radiolabelling:

yes

Test animals

Species:

rat

Strain:

Sprague-Dawley

Remarks:

Crl:CD(SD)BR

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: 6 to 10 weeks
- Weight at study initiation: 142 to 198 g
- Housing: prior to the study animals were housed up to five per cage according to sex in grid-floor polypropylene cages suspended over polypropylene trays containing soft white wood sawdust; during the study the animals were kept in individual all-glass metabolism cages suitable for the separate collection of urine, faeces and expired air
- Diet: commercial pellet diet ad libitum; fastin for 16 h prior to the administration of the test substance
- Water: ad libitum
- Acclimation period: 1 to 2 weeks

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 16 to 27
- Humidity (%): 52 to 82
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: April 1987 To: February 1988

Administration / exposure

Route of administration:

other: Gavage (Group B, C, D) and intraveneous (Group A)

Vehicle:

other: Gavage: ethanol:polyethylene glycol 200 : water (1 : 2 : 2, by volume). Intraveneous: physiological saline.

Duration and frequency of treatment / exposure:

Single dose or daily dose for 14 days

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0.5 mg/kg bw (total dose)

Remarks:

Group A - single, intravenous dose (radiolabelled test substance)

Doses / concentrations 2

Dose / conc.:

0.5 mg/kg bw (total dose)

Remarks:

Group B - single, oral dose (radiolabelled test substance)

Doses / concentrations 3

Dose / conc.:

0.5 mg/kg bw/day (nominal)

Remarks:

Group C - daily oral dose administration of non-radiolabelled test substance for 14 days followed by a one oral dose administration of radiolabelled test substance

Doses / concentrations 4

Dose / conc.:

50 mg/kg bw (total dose)

Remarks:

Group D - single, oral dose (radiolabelled test substance)

No. of animals per sex per dose / concentration:

Minimun 5 animals per sex per dose

Control animals:

no

Positive control reference chemical:

None

Details on dosing and sampling:

TOXICOKINETIC / PHARMACOKINETIC STUDY (Absorption, distribution, excretion)
- Tissues and body fluids sampled: urine, faeces, blood, tissues, cage washes, expired air
- Time and frequency of sampling:
Urine: 0-6, 6-12, 12-24, 24-48, 48-72, 72-96, 96-120, 120-144 and 144-168 h
Faeces: 0-6, 6-12, 12-24, 24-48, 48-72, 72-96, 96-120, 120-144 and 144-168 h
Expired air: 0-6, 6-12 and 12-24 h
- Tissues: bone, brain, fat (abdominal), heart, liver, skeletal muscle, residual carcass, adrenals, bone marrow, blood, gonads, kidney, lung, spleen, uterus

METABOLITE CHARACTERISATION STUDIES
- Tissues and body fluids sampled: urine, faeces
- Time and frequency of sampling:
Urine: 0-6, 6-12, 12-24, 24-48, 48-72, 72-96, 96-120, 120-144 and 144-168 h
Faeces: 0-6, 6-12, 12-24, 24-48, 48-72, 72-96, 96-120, 120-144 and 144-168 h
- From how many animals: pooled by sample type, sex and dose group
- Method type for identification: two-dimentional TLC; liquid scintillation counting
- Limits of detection and quantification: 1.5 times the background disintegration rate obtained from the measurement of pre-dose or blank samples of the same type

Statistics:

Mean values and standard derivation.

Results and discussion

Toxicokinetic / pharmacokinetic studies

Details on absorption:

Renal elimination would suggest that at least 35 to 50% of the oral dose was absorbed. The similarity in the routes of elimination between the two routes of administration however, suggest an even higher level of oral absorption.

Details on distribution in tissues:

Following a single oral low dose the liver and kidney of most animals was found to contain radioactivity. Following 14 days pre-treatment with non-radiolabelled test article, the distribution of radioactivity was similar to that in non pre-treated animals. When given as a single i. v. dose, radioactivity was more widely distributed between tissues but levels were generally low.

Details on excretion:

The elimination of radioactivity following the administration of the test substance to the rat at dose levels of 0.5 and 50 mg/ kg was essentially complete by 48 hr post-dose. Following a single oral dose at both the low and high dose levels, radioactivity was voided approximately equally between urine and faeces. Pre-treatment with non-radiolabelled test substance or the administration of a single intravenous dose at the low level did not change this pattern of excretion. In all treatment groups, renal elimination was slightly greater in females than males.

Metabolite characterisation studies

Metabolites identified:

yes

Details on metabolites:

Regardless of route or dose level the test substance was extensively degraded with metabolism possibly proceeding through side chain oxidation giving the hydroxylated propyl derivative or replacement of the propyl group by a carboxylic acid. The metabolism may even result in the degradation of the dioxolane ring to a hydroxyl or carbomyl group.

Any other information on results incl. tables

 Table 1. Mean recovery of radioactivity from male and female rats following administration of radiolabelled test substance

	Percent of administered dose
	Group A 0.5 mg/kg iv		Group B 0.5 mg/kg po		Group C 0.5 mg/kg po*		Group D 50 mg/kg po
Urine	42.9	46.3	38.7	43.8	40.6	45.6	39.2	48.7
Faeces (extract)	19.4	19.0	25.0	18.8	19.8	18.1	24.4	20.5
Faeces (residue)	22.4	20.0	25.2	19.1	28.6	21.8	23.5	16.5
Cage washings	4.9	8.5	7.0	12.5	6.5	9.8	5.6	8.4
Cage debris	0.1	0.1	N.D.	N.D.	N.D.	N.D.	0.7	N.D
Expired air	N.D.	N.D.	N.D.	N.D.	N.D.	N.D.	N.D.	N.D.
Tissues	0.1	0.1	0.1	0.1	0.1	0.1	0.1	N.D.
Carcass	N.D.	N.D.	N.D.	N.D.	N.D.	1.0	N.D.	0.2

* after 14 daily doses of unlabelled material

N.D. = Not detected (< 0.1 % dose)

 

 

At the termination of the excretion studies, mean tissue concentrations of radioactivity were generally low or below the limits of detection:

 

Group A

The highest consistent mean quantity was present in liver (males 0.021 µg equiv/g (SD 0.005) = 0.11 % dose, females 0.010 µg equiv/g (SD 0.006) = 0.06 % dose). The quantity in bone marrow was 0.051 µg equiv/g (SD 0.046) in males and 0.008 µg equiv/g (SD 0.012) in females, in blood 0.001 µg equiv/g (SD 0.001) in males and 0.004 µg equiv/g (SD 0.010) in females.

 

Group B

The only tissues where radioactivity was consistently detected were liver (males 0.012 µg equiv/g (SD 0.009) = 0.07 % dose, females 0.007 µg equiv/g (SD 0.004) = 0.06 % dose) and kidneys (males 0.004 µg equiv/g (SD 0.002) = 0.01 % dose, females 0.004 µg equiv/g (SD 0.001) = 0.01 % dose).

No radioactivity was recovered in bone marrow and blood in males. The quantity in bone marrow was 0.006 µg equiv/g (SD 0.014) in females.

 

Group C

The highest mean quantity of radioactivity in males was present in liver (0.022 µg equiv/g (SD 0.004) = 0.11 %) and kidneys (0.006 µg equiv/g (SD 0.002) = 0.01 %). No radioactivity was recovered in bone marrow and blood in males. In females, low levels were detected in more tissues of most animals. The highest concentrations were present in liver (0.018 µg equiv/g (SD 0.004) = 0.11 %). The quantity in bone marrow was 0.036 µg equiv/g (SD 0.080) and in blood 0.002 µg equiv/g (SD 0.001) in females.

 

Group D

The highest mean levels of radioactivity were observed in liver (males 0.938 µg equiv/g (SD 0.297) = 0.06 % of dose, females 0.784 µg equiv/g (SD 0.415) = 0.04 % of dose) and in males in adrenals

(0.561 µg equiv/g (SD 0.773) = < 0.01 % of dose, in females in kidneys (0.366 µg equiv/g (SD ) = < 0.01 % of dose). No radioactivity was recovered in bone marrow in males. The quantity in bone marrow was 0.144 µg equiv/g (SD 0.322) in females. The quantity in blood was 0.076 µg equiv/g (SD 0.058) in males and 0.161 µg equiv/g (SD 0.199) in females.

 

Metabolites identified:

Examination of pooled urine and faecal extracts by two-dimensional TLC indicated the test substance is extensively metabolised, there being many radiolabelled breakdown products, particularly in faeces. The products varying between groups and sexes, particularly in high dose faecal extracts. There was, however, evidence of unchanged test substance in urine of animals dosed i.v. and in the faeces of animals treated orally. Between three and eight radiolabelled components were observed in urine. Following single low doses there was evidence for M9 and M2 (except i.v. dosed females ) as well as M3 and M10 (females only) in i.v. dosed animals. In pre-treated animals with the exception of M3, M2 and M10 in male urine most of the components did not correspond with the standards. Similarly in the high dose group, only in female samples was a component observed corresponding to a standard (M9 - 49.3%). Faecal extracts contained a very large number of components, most of which were very polar exhibiting very low Rf values in system 1. In animals given single low doses by either route components corresponding to M9 (except oral dosed females), and M1 were present. These products were also observed in pre-treated male animals, but not in females where most of the components were highly polar. At the high dose samples contained many more components (24 to 29) mostly polar, but there was evidence in the faeces of females of M9, M1 and M11 or M12.

Applicant's summary and conclusion

Conclusions:

In this study performed in compliance with GLP and following a FIFRA 85-1 guideline administration of low doses of radiolabelled test substance to rats by the oral and intravenous routes resulted in similar patterns of elimination. Pre-treatment with non-radiolabelled test substance had no significant effect on the pattern of excretion or distribution of residual radioactivity. Administration of radiolabelled test substance at the high level resulted in a similar pattern of elimination with most of the dose being excreted by 48 hours. The concentrations of residual radioactivity in tissues were similar if not lower than those observed at the low dose level. Bioavailability (F) calculated is 90.7 %. This value is based on the excreted dose of 39 % in urine after oral administration and 43 % after intravenous administration in males at 0.5 mg/kg. (Bioavailability 39/43 = 90.7 %.) Regardless of route or dose level, radiolabelled test substance was extensively degraded with metabolism possibly proceeding through side chain oxidation giving the hydroxylated propyl derivative or replacement of the propyl group by a carboxylic acid. The metabolism may even result in the degradation of the dioxolane ring to a hydroxyl or carbonyl group.

Executive summary:

In this study performed in compliance with GLP and following a FIFRA 85-1 guideline, absorption, distribution, metabolism and elimination of radiolabelled test substance have been investigated following oral and intravenous administration to the Sprague Dawley rats of the Crl:CD(SD)BR strain. Studies were conducted using a low dose of 0.5 mg/kg and a high dose of 50 mg/kg (p.o). At the low oral dose level, studies were conducted with and without 14 consecutive days pre-treatment with nonradiolabelled test substance. Test substance was administered to four groups of rats, each comprising of at least five male and five female animals.

Administration of low doses of radiolabelled test substance to rats by the oral and intravenous routes resulted in similar patterns of elimination. Pre-treatment with non-radiolabelled test substance had no significant effect on the pattern of excretion or distribution of residual radioactivity. Administration of radiolabelled test substance at the high level resulted in a similar pattern of elimination with most of the dose being excreted by 48 hours. The concentrations of residual radioactivity in tissues were similar if not lower than those observed at the low dose level. Bioavailability (F) calculated is 90.7 %. This value is based on the excreted dose of 39 % in urine after oral administration and 43 % after intravenous administration in males at 0.5 mg/kg. (Bioavailability 39/43 = 90.7 %.) Regardless of route or dose level, radiolabelled test substance was extensively degraded with metabolism possibly proceeding through side chain oxidation giving the hydroxylated propyl derivative or replacement of the propyl group by a carboxylic acid. The metabolism may even result in the degradation of the dioxolane ring to a hydroxyl or carbonyl group.