Biphenyl-4,4'-diol

Repeated dose toxicity: oral

Administrative data

Endpoint:

short-term repeated dose toxicity: oral

Remarks:

combined repeated dose and reproduction / developmental screening

Type of information:

experimental study

Adequacy of study:

key study

Study period:

not stated

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Modern study conducted in accordance with OECD Test Guideline 422

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

2004

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)

Principles of method if other than guideline:

Males were treated for 42 days, with a satellite high dose group retained for a further 15 days to demonstrate recovery after treatment.
The females were treated for 14 days prior to mating and then through gestation to lactation day 4. A high dose satellite recovery group of females was also retained for fifteen days following completion of treatment.

GLP compliance:

yes

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Biphenyl-4,4'-diol

EC Number:

202-200-5

EC Name:

Biphenyl-4,4'-diol

Cas Number:

92-88-6

Molecular formula:

C12H10O2

IUPAC Name:

[1,1'-biphenyl]-4,4'-diol

Details on test material:

No further details.

Test animals

Species:

rat

Strain:

Crj: CD(SD)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Crj:CD(SD)IGS rats used but no details provided regarding supplier
- Age at study initiation: No data
- Weight at study initiation: No data
- Fasting period before study: No data
- Housing: No data

- Diet (e.g. ad libitum): no data
- Water (e.g. ad libitum): no data
- Acclimation period: no data

ENVIRONMENTAL CONDITIONS
- Temperature (°C): No data
- Humidity (%): No data
- Air changes (per hr): No data
- Photoperiod (hrs dark / hrs light): No data

IN-LIFE DATES: From: not stated To: not stated

Administration / exposure

Route of administration:

oral: gavage

Vehicle:

other: 0.5% sodium carboxymethylcellulose solution

Details on oral exposure:

REPARATION OF DOSING SOLUTIONS:

VEHICLE
- Justification for use and choice of vehicle (if other than water):0.5% sodium carboxymethylcellulose solution used as suspending agent
Males were treated for 42 days, with a satellite high dose group retained for a further 15 days to demonstrate recovery after treatment.
The females were treated for 14 days prior to mating and then through gestation to lactation day 4. A high hose satellite recovery group of females was also retained for fifteen days following completion of treatment.

Analytical verification of doses or concentrations:

not specified

Details on analytical verification of doses or concentrations:

no data

Duration of treatment / exposure:

Males were treated for 42 days, with a satellite high dose group retained for a further 15 days to demonstrate recovery after treatment.
The females were treated for 14 days prior to mating and then through gestation to lactation day 4. A high dose satellite recovery group of females was also retained for fifteen days following completion of treatment.

Frequency of treatment:

Daily

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/kg bw/day (actual dose received)

Doses / concentrations 2

Dose / conc.:

8 mg/kg bw/day (actual dose received)

Doses / concentrations 3

Dose / conc.:

40 mg/kg bw/day (actual dose received)

Doses / concentrations 4

Dose / conc.:

200 mg/kg bw/day (actual dose received)

No. of animals per sex per dose:

twelve; an additional five rats per sex were allocated to the satellite groups for retention through the recovery phase.

Control animals:

yes, concurrent vehicle

Details on study design:

As a screening study this investigation was limited to the parental generation and F1 offspring only. The repeated adminstration phase for males (42 days) and females (14 days) prior to mating provides some subacute toxicity data and the treatment of females through gestation gives some reproductive and developmental toxicity information.

The males and females were dosed for up to 42 days by oral gavage and this subacute exposure was used to address the short-term toxicology endpoints. Clinical signs, bodyweight gain, food consumption haematology, clinical chemistry and urinalysis parameters were recorded together with a limited functional observation battery, organ weights and macroscopic and microscopic examinations at termination.

Positive control:

Not applicable

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: at weekly intervals - assessment in homecage, then in observers hands and then outside the homecage. Assessments included posture, sleeping, locomotion,vocalisations, tremors and convulsions, response to capture and handling, salivation, grading of heart beat, body temperature, exophthalmus and pupil size, exhibition of any discoloration of fur, skin or lacrimation. Outside the cage the assessment of posture, grooming, vocalisations, occurrence of straub tail, gait, tremor, convulsion pilo-erection and palpebral opening; exploration and respiratory rate and any exhibition of stereotypy or bizarre behaviour.

A functional assessment was completed on the final day of treatment to assess various reflex responses.

BODY WEIGHT: recorded on days 1, 7, 14, 21, 28, 35 and 42 of treatment and days 1, 7, and 14 of recovery for males.
Females were weighed on days 1, 7, and 14 of treatment; days 0, 7, 14 and 20 of pregnancy and days 0 and 4 of lactation
Bodyweights and bodyweight gains are reported.

Food consumption was recorded for the males and for the satellite females (treated at 200 mg/kg) on days 1-2, 7-8, 14-15, 29-30, 35-36 and 41-42 and then days 6-7 and 13-14 of the recovery phase.

Urinalysis was performed on Day 31 and 32 for males and females respectively. Parameters assessed included colour, turbidity, pH, protein, glucose, ketone and bilirubin levels, occult blood, urobilinogen and presence in urinary sediment of crystals by incidence and type/shape and urinary specific gravity.

Clinical pathology in the form of standard haematology and biochemical parameters were assessed on Day 43 of treatment and on Day 15 of the recovery phase for male rats and on Day 5 of lactation for the females.

Organ weights were recorded on Day 43 of treatment and on Day 15 of the recovery phase for male rats and on Day 5 of lactation for the females.


Necropsy was completed on termination of treatment or after completion of the recovery phase or on day 5 of lactation. Macroscpic findings were recorded at each scheduled necropsy. Histopathological findings were documented for tissues sampled following each of the scheduled necropsy events. The list of tissues examined was in accordance with the test guideline.

Sacrifice and pathology:

SACRIFICE
- Male animals: All surviving animals following day 42 of treatment or on day 15 of the recovery phase.
- Maternal animals: All surviving animals on day 5 of lactation or on day 15 for the satellite animals in the recovery phase.

GROSS NECROPSY
- Gross necropsy consisted of external and internal examinations including the cervical, thoracic, and abdominal viscera. Certain organ weight parameters were also recorded at termination.

HISTOPATHOLOGY / ORGAN WEIGHTS
The tissues indicated in the attached table were prepared for microscopic examination and weighed, respectively.

Other examinations:

Additional examinations related to the reproductive toxicity/developmental toxicity screening were included and have been detailed in the summary presented in the relevant section.

The study design was based on test guideline OECD 422 and included assessmeny of various reproductive and developmental toxicity parameters including:
oestrous cycling for females in the pre-treatment period, treatment period and during the mating period

reproductive performance parameters - copulation index, number of pregnant females, fertility index, length of pairing time to copulation

pup development parameters including number of pregnant females and those with live neonates, gestation length, number of corpora lutea, number of implantations, various parameters related to lactation Day 0 indices and for lactation Day 4; and sex ratio of pups on day 4.
Pup weights, number of live neonates and morphological findings for live and dead pups

Statistics:

No data

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Description (incidence and severity):

daily observations showed no adverse reactions; detailed clinical assessment revealed no treatment related changes

Mortality:

no mortality observed

Description (incidence):

daily observations showed no adverse reactions; detailed clinical assessment revealed no treatment related changes

Body weight and weight changes:

no effects observed

Description (incidence and severity):

bodyweights for males and females showed no significant differences from controls at any timepoint.

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

Food consumption showed no significant treatment related differences

Food efficiency:

not examined

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

not examined

Ophthalmological findings:

not examined

Haematological findings:

no effects observed

Description (incidence and severity):

No significant treatment related changes

Clinical biochemistry findings:

no effects observed

Description (incidence and severity):

No significant treatment related changes

Urinalysis findings:

effects observed, treatment-related

Description (incidence and severity):

Urinary turbidity, specific gravity changes

Behaviour (functional findings):

not examined

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

relative liver weights increased for high dose males

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

darkened enlarged livers at 200 mg/kg

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

liver histopathology in males at 200 mg/kg

Histopathological findings: neoplastic:

not examined

Details on results:

Oral administration of 4,4'-biphenyldiol at dose levels of 8, 40 or 200 mg/kg bw/day did not cause death or a moribund condition in any animals. None of the scores obtained during detailed clinical observations differed in a biologically significant manner between the control and the compound-treated groups.
No apparent changes were observed in general clinical conditions, except that urine in the 200 mg/kg bw/day treated group became cloudy with elapse of time after excretion. Urinalysis was performed on treatment days 31 and 32 in male and female rats, respectively, calcium oxalate-like urinary crystal sediments were found in males given 200 mg/kg and in females given 40 or 200 mg/kg. Turbidity was enhanced at dose levels of 40 or 200 mg/kg, and urinary specific gravity was decreased in these females. These changes in urine parameters were not found when urinalysis was performed 11 days after cessation of the treatment (on day 11 of recovery) in either sex for the satellite animals.
Body weight, weight gain and food consumption were not affected by treatment at any dose level in either sex. No animals showed any abnormality in functional parameters after the final treatment.
At necropsy on termination of the treatment, no apparent effects of the compound were found on haematological or blood-biochemical examination at any dose level of the compound in either sex.

Results are presented in tabular form below. In conclusion, we propose to use a NOAEL of 40 mg/kg bw/day.

At 40 mg/kg bw d in males only, increased (+10%) absolute liver weight, not statistically significant, was observed. A slight increment (+6%), not statistically significant, in absolute kidney weight was also observed. No effects on females were observed at this dose level.
Histopathological effects in males were considered of no toxicological significance since no substantial variation in respect to control was observed. No effects on females were observed at this dose level.
Turbidity of the urine was only reported in 1/5 males due to presence of oxalate like crystal formation (2/5). Also in 1/5 females turbidity of urine was observed, but in this case only 1/5 animal showed presence of oxalate like crystal formation. A statistically significant decrement of Specific Gravity (-1%) was
observed in urine, but only for females . This decrement was not considered to be biologically relevant and/or adverse.
Since there were no effects on kidney and on liver at 40 mg/kg and all those effects observed at the high dose level were reversible in nature, it can be concluded that effects observed at 40 mg/kg bw day represent a NOAEL (No Observed Adverse Effect Level) for this compound.

Effect levels

1

Key result

Dose descriptor:

NOEL

Effect level:

8 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: see 'Remark'

2

Key result

Dose descriptor:

NOAEL

Effect level:

40 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: see 'Remark'

Target system / organ toxicity

1

Key result

Critical effects observed:

yes

Lowest effective dose / conc.:

200 mg/kg bw/day (nominal)

System:

hepatobiliary

Organ:

liver

Treatment related:

yes

2

Key result

Critical effects observed:

yes

Lowest effective dose / conc.:

200 mg/kg bw/day (actual dose received)

System:

urinary

Organ:

kidney

Treatment related:

yes

Any other information on results incl. tables

Tabulated summary of toxicologically important findings in the reproductive and developmental toxicity screening study in rats

		Dose levels for main study				Dose levels for recovery groups
		0	8	40	200	0R	200R
Organ weight %variation compared with control
Males	Liver	--	-2%	10%	8% **	--	3%
	Kidney	--	-1%	6%	2%	--	-2%
Organ weight %variation compared with control
Females	Liver	--	-9%	-6%	-2%	--	1%
	Kidney	--	-4%	2%	-5%	--	4%
Histopathology
Males	Liver centrilobular hypertrophy	0/5	0/5	0/5	2/5	0/5	0/5
	Liver periportal fatty change ##	5/5	5/5	5/5	5/5	5/5	5/5
	Kidney Eosinophilic body ##	2/5	2/5	5/5	5/5	2/5	5/5
Histopathology
Females	Liver centrilobular hypertrophy	0/5	0/5	0/5	0/5	0/5	0/5
	Liver periportal fatty change ##	4/5	5/5	3/5	4/5	1/5	3/5
	Kidney Eosinophilic body ##	0/5	0/5	0/5	0/5	0/5	0/5
Urinalysis
Males	Turbidity	0/10	0/5	1/5	10/10	0/5	0/5
	Crystals (few)	10/10	4/5	3/5	0/10	0/5	0/5
	Crystals (abundant)	0/10	1/5	2/5	10/10	0/5	0/5
	Oxalate-like crystals	0/10	0/5	0/5	8/10	0/5	0/5
	Specific Gravity	--	--	--	--	--	-1%
Urinalysis
Females	Turbidity	0/7	0/7	2/7	6/7	0/5	4/5
	Crystals (few)	5/7	3/7	6/7	0/7	5/5	1/5
	Crystals (abundant)	0/7	2/7	1/7	7/7	0/5	4/5
	Oxalate-like crystals	0/7	0/7	1/7	6/7	0/5	4/5
	Specific Gravity	--	--	-1% *	-2% **	--	-1%

##       no toxicological significance or biological importance since the treated groups responded similarly to control with no notable variation.
*        p<0.05
**      p<0.01

Bodyweights for males and satellite females during treatment and during the recovery phase were similar to controls. No notable difference in bodyweight or bodyweight gain was recorded for treated, pregnant females in comparison with controls throughout the treatment, pregnancy or lactation phases. Food consumption, similarly, for males, satellite females and the treated dams showed no changes from controls that were indicative of a toxicologically significant or treatment-related effect.

The incidence of clinical signs generally revealed no notable differences between treated and control groups. However, voiding of cloudy, white turbid urine was observed frequently for the majority of males, satellite females and the pregnant females following dosing at 200 mg/kg bw/day but no observed among any rats dosed at 0, 8 or 40 mg/kg bw/day. The detailed clinical assessment in the home cage and during handling or in an outside arena also showed no treatment-related clinical response among any of the rats.

Functional findings (assessment of Preyer's reflex; pupillary reflex; visual placing; startle response; pain response; hindlimb withdrawal; corneal reflex and righting reflex) showed no differences between treated and control rats.

Urinary findings are tabulated above. No toxicologically significant differences between treated and control rats (males, satellite females or the treated dams) were apparent for colour, pH, protein, glucose, ketone,bilirubin, occult blood or urobilinogen levels.

For the males and satellite females a similar pattern of response was noted at termination an on day 11 of the recovery period - increased turbidity in the high dose group, 200 mg/kg bw/day, on day 31 but no effects by day 11 of recovery. Examination of urinary sediment revealed few crystals in the control and increasingly abundant crystal presence with increasing dose and examination of the shape indicated increased incidence of calcium oxalate type crystals in the high dose group and less frequently in males dosed at 40 mg/kg bw/day.

A similar pattern was observed in the treated pregnant rats, slight to moderate urinary turbidity at the high dose with a higher frequency of calcium oxalate-like crystals. The urinary specific gravity was significantly lower for the 40 and 200 mg/kg bw/day groups (-1 and -2% respectively; p<0.05 and p<0.01 respectively).

There were no changes in any of the haematology or biochemical parameters to indicate any treatment-related systemic toxicity for males, satellite females or the treated females at the end of the treatment period or following the recovery phase.

Absolute and relative organ weights showed no evidence of any consistent treatment-related effects in males and females. In particular there were no significant differences between treated and control groups for kidney weights and only the high dose males showed a significant increase in relative liver weight with no effect apparent following the recovery phase. There were no indications from organ weights that the potential target organs, liver or kidney, were affected by treatment at 40 mg/kg bw/day.

The macroscopic findings revealed dark, enlarged livers for all male rats dosed at 8, 40 or 200 mg/kg bw/day and for all the control rats. No liver effects were apparent for any females on Day 5 of lactation and the incidence of renal pelvic dilation in the kidneys was comparable across treated and control groups, as was the incidence of small spleen or small thymus. None of these macroscopic observations were considered to represent an adverse effect of treatment.

No treatment-related histopathological changes of toxicological significance were identified for the females. In the high dose male group two rats had centrilobular hypertrophy and five showed a periportal fatty change, the latter achieving statistical significance in comparison with controls. The changes were graded on a five point scale (negative,very slight, slight, moderate and severe) and all of the reactions observed in the male livers were graded as very slight.

In the absence of any confirmatory clinical or microscopic pathology, the minor changes in relative liver weight were considered not to be toxicologically signifcant. The induction of liver enzymes is non-specific response and may be considerd an adaptive response to increased metabolic load. The crystal deposition at the high dose level did not affect kidneys in rats dosed at 40 mg/kg bw/day. The No Observed Adverse Effect Level for systemic toxicity based on sub acute exposure of rats in this screening study is therefore considered to be 40 mg/kg bw/day.

Applicant's summary and conclusion

Conclusions:

Treatment up to 200 mg/kg bw/d did not affect the reproductive performance of parental animals or the early development of their offspring. The no observed adverse effect level (NOAEL) for repeat dose toxicity of 4,4'-biphenyldiol is considered to be 40 mg/kg bw/d for both sexes of animals. The NOAEL for reproductive/developmental toxicity is considered to be 200 mg/kg/day for females and males, and the NOAEL for offspring is considered to be 200 mg/kg/day.

Executive summary:

A combined repeat dose and reproductive/developmental toxicity screening test was conducted in rats according to the OECD Test Guideline 422 with 4,4'-biphenyldiol.

At the high dose level of 200 mg/kg bw/d, excreted urine became cloudy over the treatment period. Urinalysis revealed turbidity for males and females dosed at 200 mg/kg bw/d but only an isolated case at 40 mg/kg bw/d. Calcium oxalate-like urinary crystal sediment was found in the males given 200 mg/kg bw/d and in the females given 40 or 200 mg/kg bw/d. Urinary specific gravity was marginally decreased in the females given doses of 40 or 200 mg/kg bw/d. At necropsy after the final treatment, the high dose, 200 mg/kg bw/d, affected male livers - increased relative weights and altered the histopathological appearance, including development of centrilobular hepatocyte hypertrophy and incrased frequency of very slight periportal fatty change. Fourteen days after the final treatment the recovery group of males and the satellite females demonstrated that all of the changes caused by the compound had disappeared and no delayed toxicity was evident. The no observed adverse effect dose level (NOAEL) for repeat dose toxicity of 4,4'-biphenyldiol is considered to be 40 mg/kg bw/d for both sexes of animals. Treatment up to 200 mg/kg bw/d did not affect the reproductive performance of parental animals or the early development of their offspring. The NOAEL for reproductive/developmental toxicity is considered to be 200 mg/kg bw/d for females and males, and the NOAEL for offspring is considered to be 200 mg/kg bw/d.