Acetic acid, 2-[(5-chloro-8-quinolinyl)oxy]-, 1-methylhexyl ester

Repeated dose toxicity: oral

Administrative data

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

10 May 1988 to 12 August 1988

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP compliant, guideline study, available as unpublished report, no restrictions, fully adequate for assessment

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1989

Report date:

1989

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity Study in Rodents)

Deviations:

not applicable

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

heptan-2-yl [(5-chloroquinolin-8-yl)oxy]acetate

EC Number:

619-447-3

Cas Number:

99607-70-2

Molecular formula:

C18H22ClNO3

IUPAC Name:

heptan-2-yl [(5-chloroquinolin-8-yl)oxy]acetate

Details on test material:

- Name of test material (as cited in study report): CGA185072 technical
- Analytical purity: 91.6%

Test animals

Species:

rat

Strain:

other: Tif: RAIf rat, Sprague-Dawley derived

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: 4-5 weeks old
- Weight at study initiation: 101.9 - 131.7 g (males), 102.8 - 131.9 g (females)

IN-LIFE DATES: From: 10.05.1988 To: 12.08.1988

Administration / exposure

Route of administration:

oral: feed

Vehicle:

other: diet

Details on oral exposure:

DIET PREPARATION
- Rate of preparation of diet (frequency): monthly
- Mixing appropriate amounts with (Type of food): the test material was admixed to standard rodent diet. As it was found that pelleting of food resulted in a loss of test material, the treated food was used in pulverized form

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Analyses were done with the first and the last batch prepared using a HPLC method.
The analytically determined concentrations ranged from 92.8 to 102.3% of the nominal concentrations. The food mixes were homogeneous (-6% to +4% of mean value) and stable at room temperature over at least 35 days. The analytical data thus indicated that the mixing procedure was adequate and that the variance between nominal and actual dosage was acceptable.

Duration of treatment / exposure:

The rats were exposed for 85 days to treated diet and some were retained untreated (fed normal diet only) for a recovery period that ended on day 114

Frequency of treatment:

Continuous in diet

Doses / concentrations

Doses / concentrations 1

Remarks:

Doses / Concentrations:
0, 30, 150, 1000, 6000 ppm
Basis:
nominal in diet

Doses / concentrations 2

Remarks:

Doses / Concentrations:
2.039, 9.66, 63.89 and 384.2 mg/kg bw/day in males and 2.036, 10.23, 68.51 and 407.3 mg/kg bw/day in females
Basis:
actual ingested

No. of animals per sex per dose:

10

Control animals:

yes, plain diet

Details on study design:

10 males and 10 females per test group plus 10 males and 10 females for each recovery group

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: animals were checked twice daily for signs of toxicity and mortality

BODY WEIGHT: Yes
- Time schedule for examinations: body weight were taken pretest and weekly during the treatment period.

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study): Yes
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: Yes
- Food and water consumption were recorded weekly

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: pretest and at the end of the treatment (day 85) or recovery period (day 114)
- Dose groups that were examined: control and high dose group animals

HAEMATOLOGY/CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: blood was collected from surviving animals at the end of the treatment period (n=20) and at the end of the recovery period (n=10)
- Anaesthetic used for blood collection: no data
- Animals fasted: Yes (overnight)
- A full guideline compliant list of haematology and clinical chemistry parameters was investigated for terminal and recovery phase blood samples

Sacrifice and pathology:

GROSS PATHOLOGY: Yes
- selected organs weighed (all animals)
HISTOPATHOLOGY: Yes
- The sole decedent in the high dose group, all animals killed at the scheduled treatment termination or at the end of the recovery phase were subject to necropsy in accordance with test guidelines and preservation and preparation of a full list of tissues for histopathology

Statistics:

Univariate standard methods were applied to the data. Each treated group was compared to the control group (Lepage test). In addition a trend test (Jonckheere test) was applied considering all groups.

Results and discussion

Results of examinations

Clinical signs:

effects observed, treatment-related

Mortality:

mortality observed, treatment-related

Body weight and weight changes:

no effects observed

Food consumption and compound intake (if feeding study):

no effects observed

Water consumption and compound intake (if drinking water study):

effects observed, treatment-related

Ophthalmological findings:

no effects observed

Haematological findings:

effects observed, treatment-related

Clinical biochemistry findings:

effects observed, treatment-related

Urinalysis findings:

effects observed, treatment-related

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Gross pathological findings:

effects observed, treatment-related

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Histopathological findings: neoplastic:

not examined

Details on results:

CLINICAL SIGNS AND MORTALITY
- One male at 6000 ppm died

BODY WEIGHT AND WEIGHT GAIN
- Body weight gains for high dose males were slightly reduced and the females were slightly lighter than controls but no clear dose relationship was established

WATER CONSUMPTION
- Water consumption was higher (+20%) for the high dose group compared with control but returned to normal when treated diet was withdrawn in the recovery phase

HAEMATOLOGY
- High dose males (6000 ppm) showed a slight prolongation of the prothrombin time, which was not detected in the recovery group. In the absence of any other haematological changes, this isolated finding is considered to be of doubtful toxicological significance

CLINICAL CHEMISTRY
- The plasma glucose level was lower in males treated at 6000 ppm, higher bilirubin levels were found in males treated at 1000 and 6000 ppm, lower cholesterol levels were noted in the top dose group females. All parameters were normal at the end of the recovery period

URINALYSIS
- The high dose group males excreted greater volumes of less concentrated urine (reduced relative density) compared with other groups. This was consistent with higher water intake by this group.

ORGAN WEIGHTS
- Mean absolute and relative liver weights were reduced in males and females treated at 1000 and 6000 ppm. A trend for decreased kidney weights was noted in the males treated at 1000 ppm and above and - as a slight tendency - also in the top dose group females. The recovery groups showed no differences between treated groups and controls

GROSS PATHOLOGY
- One high dose (6000 ppm) male died on day 63. Post mortem investigations revealed acute nephritis, hydronephrosis with multifocal calcifications and inflammation of the urinary bladder. The findings were considered to be treatment-related.
- For animals terminated at the end of treatment with test diet, dilated kidneys were seen in two males from the high dose group (6000 ppm), one of these was the decedent that had died prematurely. In the recovery group, four additional males from the top dose group were found with the same diagnosis and one male from the same group had a dilated urinary bladder. No other notable pathological changes were evident

HISTOPATHOLOGY: NON-NEOPLASTIC
- Hydronephrosis was evident at the end of treatment for 3/10 males treated at 6000 ppm. The same observation was made in 4/9 males from the recovery group and in the individual which died prematurely. The finding was accompanied by inflammatory and fibrotic changes in the renal cortex. Hyperplasia and inflammatory cell infiltrations of the urinary bladder were found in 1/10 males at the first sacrifice, in the male which had died and in 4/9 males from the recovery group. The same observation was made in one male treated at 1000 ppm

Effect levels

Dose descriptor:

NOAEL

Effect level:

150 ppm

Sex:

male/female

Basis for effect level:

other: see 'Remark'

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

The analytically determined concentrations ranged from 92.8 to 102.3% of the nominal concentrations. The food mixes were homogeneous (-6% to +4% of mean value) and stable at room temperature over at least 35 days. The analytical data thus indicated that the mixing procedure was adequate and that the variance between nominal and actual dosage was acceptable.

The calculated mean daily intake of cloquintocet-mexyl based on the analytically determined concentrations was 2.039, 9.66, 63.89 and 384.2 mg/kg bw/day in males and 2.036, 10.23, 68.51 and 407.3 mg/kg bw/day in females.

Table 1: Cloquintocet-mexyl: 3 month toxicity study in rats - Mean body weight and body weight gain

ppm	0	30	150	100	6000
Males Pretest (g)	118.9	120.4	115.8	117.2	119.4
Week 13	477.9	512.8	473.2	475.9	456.3
Body weight gain pretest-week 13	359	392.4	357.4	358.7	336.9
(% of control)					94
Week 17	517.6	561.7	505.4	535.6	499.1
Females
Week 13	115.5	113.4	114.9	111.2	115.0
Body weight gain pretest-week 13 (% of control)	309.2	292.2	297.8	297.8	294.9
Week 17	327.4	305.5	314.0	314.0	315.5

 

Table 2: Cloquintocet-mexyl: 3 month toxicity study in rats - Blood chemistry data (week 14)

	Males					Females
ppm	0	30	150	1000	6000	0	30	150	1000	6000
Glucose (mmol/l)	8.47	8.19	8.49	8.17	7.69*	7.23	7.22	7.08	6.86*	6.89
Bilirubin (mmol/l)	3.23	2.92	3.13	3.91**	4.15**	3.14	3.07	2.93	3.37**	3.47**
*: p 0.05, **: p 0.01, Lepage test

 Table 3: Cloquintocet-mexyl: 3 month toxicity study in rats – Organ weights

Dose level (ppm)	0	30	150	1000	6000
Males
Liver weight (g	18.63	18.19	17.60	15.36*	14.79*
Liver to b.w. ratio	41.04	37.42	38.37	35.25*	34.67*
Kidney weight (g)	2.926	2.895	2.774	2.581*	2.634
Kidney to b.w. ratio	6.430	5.987	6.092*	5.924*	6.202
Females
Liver weight (g	10.84	9.774	10.36	9.493	9.090*
Liver to b.w. ratio	38.58	35.79	37.06	35.20	33.43
Kidney weight (g)	1.867	1.802	1.907	1.824	1.693
Kidney to b.w. ratio	6.645	6.620	6.825	6.760	6.233
*: p 0.05, **: p 0.01, Lepage test

Table 4: Cloquintocet-mexyl: 3 month toxicity study in rats - Histopathology data

	Males					Females
ppm	0	30	150	1000	6000	0	30	150	1000	6000
Kidney
Hydronephrosis: 14 weeks	0	0	0	0	3	0	0	0	0	0
18 weeks	0	0	0	0	4	0	0	0	0	0
Urinary bladder
Hyperplasia
14 weeks	0	0	0	1	1	0	0	0	0	0
18 weeks	0	0	0	0	4	0	0	0	0	0
Inflammatory cell infiltration
14 weeks	0	0	0	1	1	0	0	0	0	0
18 weeks	0	0	0	0	4	0	0	0	0	0

 

Applicant's summary and conclusion

Conclusions:

Based on the effects seen in the bladder of males the NOAEL was 150 ppm, equivalent to a mean daily intake of 9.66 mg/kg in males and 10.2 mg/kg in females

Executive summary:

Groups of male and female Tif: RAIf, Sprague-Dawley derived rats were treated for three months with cloquintocet-mexyl via dietary admixture and additional animals were retained for a post-treatment recovery phase to check for reversibility of effects. The dose levels used were 0 (control), 30, 150, 1000 and 6000 ppm. The study methods were compliant with the OECD test guideline and a full list of parameters of systemic toxicity was investigated.

Subchronic dietary treatment for 3 month with cloquintocet-mexyl caused mortality in one male rat at a high dose of 6000 ppm. In males rats the target organs of toxicity were the kidney, which showed hydronephrosis and chronic inflammatory changes, and the urinary bladder indicated by hyperplasia and inflammation. Based on the effects seen in the bladder of males the NOAEL was 150 ppm, equivalent to a mean daily intake of 9.66 mg/kg in males and 10.2 mg/kg in females.