N,N'-diphenylguanidine monohydrochloride

Endpoint summary

Description of key information

The NOAEL in an oral repeated dose toxicity study with an structural analogue substance (CAS 102 -06 -7) was determined to be 10 mg/kg bw/d.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Link to relevant study records

Reference

Endpoint:

chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1970

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 452 (Chronic Toxicity Studies)

Principles of method if other than guideline:

Male chinchilla rabbits were treated orally with a water solution of the test item daily for 8 months. The effects of the test item on the liver were determine by measuring the retention coefficients of bilirubin and bromsulfalein.

GLP compliance:

no

Limit test:

no

Species:

rabbit

Strain:

Chinchilla

Sex:

male

Route of administration:

oral: unspecified

Vehicle:

water

Analytical verification of doses or concentrations:

no

Duration of treatment / exposure:

8 months

Frequency of treatment:

daily

Dose / conc.:

0.025 mg/kg bw/day (nominal)

Dose / conc.:

0.5 mg/kg bw/day (nominal)

Dose / conc.:

5 mg/kg bw/day (nominal)

No. of animals per sex per dose:

6 male rabbits per dose

Control animals:

yes, concurrent no treatment

Clinical biochemistry findings:

effects observed, treatment-related

Description (incidence and severity):

The bilirubin and bromsulfalein retention coefficinets were significantly higher for the highest treatment dose of 5 mg/kg than the ones in the control group.
No significant differences to the control group were observed in the lower concentration of 0.025 and 0.5 mg/kg.

Details on results:

The excretion function of the liver was drastically changed in the tretment group 5 mg/kg with bromsulfalein.

Key result

Dose descriptor:

NOAEL

Effect level:

0.5 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

clinical biochemistry

Key result

Dose descriptor:

LOAEL

Effect level:

5 mg/kg bw/day (nominal)

Based on:

test mat.

Sex:

male

Basis for effect level:

clinical biochemistry

Key result

Critical effects observed:

yes

Lowest effective dose / conc.:

5 mg/kg bw/day (nominal)

System:

hepatobiliary

Organ:

liver

Treatment related:

yes

The reaction coefficients of bromsulphalein in doses 0.025 and 0.5 mg/kg bw were significantly not different than the coefficients of the control group. The differences and changes in the coefficients of bilirubin were not significantly different to the control group in all tested doses.

In the treatment of 5 mg/kg bw sufficient increase in the retention coefficient of bilirubin from the fifth month onwards was observed. The increase in the coefficients at the end of the experiment in this was 23.4 %.

Dose (mg/kg bw)	Time of observations (months)
	1	2	3	4
	Retention coefficients - Bromsulfalein
Control	2.81 ± 0.64	2.2 ± 0.46	3.62 ± 0.58	4.44 ± 0.40
0.025 0.5 5.0	2.84 ± 0.51 3.09 ± 0.78 4.99 ± 0.56	2.67 ± 0.38 2.96 ± 0.84 6.35 ± 0.52	1.90 ± 0.70 2.96 ± 0.73 10.08 ± 1.12	3.56 ± 0.48 3.20 ± 0.54 17.08 ± 1.02
t	-	6.0	5.12	11.49
P	-	<0.01	<0.01	<0.001
	Retention coefficients - Bilirubin
Control	13.02 ± 0.75	13.30 ± 0.95	13.41 ± 0.84	14.44 ± 0.80
0.025 0.5 5.0	13.85 ± 0.57 14.96 ± 0.67 14.64 ± 0.94	12.72 ± 0.71 14.32 ± 0.67 14.14 ± 0.64	13.51 ± 0.83 13.37 ± 0.95 17.00 ± 0.89	14.35 ± 1.10 15.52 ± 0.89 17.81 ± 0.96
t	-	-	2.8	3.26
P	-	-	<0.05	<0.05

 

Conclusions:

In conclusion, intoxication in rabbits treated with the test item at dose level of 5 mg/kg bw showed a disturbance in the excretion function of the liver.

Executive summary:

The effects of the test item on the function of the liver in male chinchilla rabbits were determined in a chronic study in the span of 8 months. The test item was administered orally daily in water solution for 8 months. Three treatment groups of 6 male rabbits were tested in concentrations of 0.025, 0.5 and 5 mg/kg body weight/d. The retention coefficients of bilirubin and bromsulfalein were determined in blood samples. Based on these retention times the effects on the liver of the tested animals wes determined. After the treatment period, it was determined that in the highest tested dose of 5 mg/kg bw/d a significant effect on the excretion function of the liver was observed. In treatments with 0.025 and 0.5 mg/kg bw/d no significant differences with the control group were observed. Therefore, the NOEAL was determined to be 0.5 mg/kg bw/d and the LOAEL was determined to be 5 mg/kg bw/d.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

NOAEL

10 mg/kg bw/day

Study duration:

subacute

Species:

rabbit

Quality of whole database:

GLP and guideline study with an structural analogue substance.

Organ:

other: significantly high values for platelet counts in females as well as significantly low values for blood glucose in males in the 30 mg/kg group

Repeated dose toxicity: inhalation - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: inhalation - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - systemic effects

Endpoint conclusion

Endpoint conclusion:

no study available

Repeated dose toxicity: dermal - local effects

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Read-Across approach

Data on repeated dose toxicity are available with a structural analogue substance (CAS 102 -06 -7) which are suitable and adequate to fulfill this endpoint. For Read-across justification please refer to the respective IUCLID Section.

Repeated dose toxicity with CAS 102 -06 -7

The repeated dose toxicity of DPG in corn oil was evaluated atdaily dose levels of 0, 10, 30 and 90 mg/kg in a 28-day oral repeated dose toxicity study in Crj:CD(SD) rats performed following the OECD guideline 407 and GLP. Five each of males and females were assigned to each group, and recovery groups were formed with five each of males and females, assigned to the control group and the maximum dose group. Clinical signs, body weight, food consumption, hematology, blood coagulation, blood chemistry, urinalysis, organ weights and histological examinations were conducted.

Dead or moribund animals were observed in both sexes in the 90 mg/kg group during the administration period. One male died during week 4, and 7 females died or were moribund during weeks 2~4, so the mortality rate was 10% for males and 70% for females. The results of the pathological examination did not exhibit any changes correlating to the cause of death. During observations on the general conditions, salivation was observed in both sexes in the 30 mg/kg. Clinical symptoms including salivation, lying prone on the stomach, lying laterally, staggered gait, reduction in spontaneous motor activity and startle response were observed in both sexes in the 90 mg/kg group. Furthermore, in the dead or moribund females in the 90 mg/kg group, emaciation, fur loss on the rear limbs and dirty fur were observed. The symptoms observed during the administration period were not observed during the recovery period, and indicates reversibility. During the administration period, significantly low values or a tendency of low values was noted for body weight and food consumption in both sexes in the 90 mg/kg group. Also, significantly low values or a tendency of low values was noted for weight gain and total food consumption during the 4^thweek of administration. In males, significantly low values were observed for the mean food efficiency at the 4^thweek of administration. Reversibility from these changes was noted during the recovery period. The results of the hematological examination revealed no impact of the administration of the test substance on males. In females, significantly high values were noted for platelet counts in the 30 mg/kg group. There was one survivor in the 90 mg/kg group where a trend of high values was noted for hematocrit values, hemoglobin, red blood cell count, platelet count, neutrophil ratio, monocyte ratio and large unstained cell ratio, and a trend of low values was noted for lymphocyte ratio. At the end of the recovery period, neither sex exhibited any significant differences between the control group and the test substance group. The results of the blood coagulation examinations revealed one surviving case where a trend of high values were noted for fibrinogen by the end of administration in females in the 90 mg/kg group, but if this was excluded, differences were not noted between the control group and the test substance group for both sexes. Blood chemistry examination revealed significantly low values in blood glucose in males in the 30 and 90 mg/kg groups, and significantly high values in blood urea nitrogen, total bilirubin, A/G ratio, ALT and alkaline phosphatase in males in the 90 mg/kg group. A tendency for high values in total cholesterol, total protein, albumin, sodium, chloride, calcium, inorganic phosphorus and ALT was noted in one survivor by the end of administration in females in the 90 mg/kg group. At the end of the recovery period, slightly low values were noted in the males in the 90 mg/kg group. Urinalysis revealed an increase in urine volume and a decrease in specific gravity in both sexes in the 90 mg/kg group. Furthermore, there was an increase in ketone bodies and negative protein. At the end of the recovery period, significantly low values were noted in specific gravity in males in the 90 mg/kg group. Results of the organ weight measurements did not indicate differences that suggest a clear impact of administration of the test substance. Histopathological examination results and necropsy findings revealed emaciation in the moribund and dead animals. Additionally, while the toxicological significance is not clear, the liver turned brown in males in the 30 mg/kg group and in both sexes in the 90 mg/kg group, while the eardrums were observed to turn red in both sexes in the 90 mg/kg group. Pathological examinations revealed hydropic changes in renal collecting tubules in both sexes in the 90 mg/kg group. In the dead and moribund animals, there was a higher rate of incomplete uterus findings. However, there were only a few cases but atrophied or nuclear decay of the thymus, hydropic or hemorrhagic lung, liver congestion or necrosis, or dilation of the kidney was also noted. Furthermore, while the toxicological significance is not clear, a reduction in the fatty change in the liver was noted in males in the 30 and 90 mg/kg groups.

From the results given above, since salivation was noted in both sexes and there were significantly high values for platelet counts in females as well as significantly low values for blood glucose in males in the 30 mg/kg group, the NOEL is considered to be 10 mg/kg/day for both sexes.

Supporting study on repeated dose toxicity: oral

The effects of the test item on the function of the liver in male chinchilla rabbits were determined in a chronic study in the span of 8 months. The test item was administered orally daily in water solution for 8 months. Three treatment groups of 6 male rabbits were tested in concentrations of 0.025, 0.5 and 5 mg/kg body weight. The retention coefficients of bilirubin and bromsulfalein were determined in blood samples. Based on these retention times the effects on the liver of the tested animals was determined. After the treatment period, it was determined that in the highest tested dose of 5 mg/kg an effect on the excretion function of the liver was observed.

Conclusion:

Findings of the supporting study are in line with total bilirubin increase observed with the read-across substance and support the read-across approach. However, under the conditions of the supporting study this effect cannot be judged as adverse. Therefore, the NOEL of 10 mg/kg bw with the structural analogue is taken into account as key value for DNEL derivation and Risk Assessment.

Justification for classification or non-classification

Classification, Labelling, and Packaging Regulation (EC) No 1272/2008

In addition to the 28-day repeated dose toxicity study summarized above, the structural analogue substance DPG (CAS 102-06-7) has also been assessed in a sub-chronic toxicity study in rats (NTP Technical Report on Toxicity Studies of 1,3-Diphenylguanidine (CAS No. 102-06-7), NIH Publication 95-3933, 1995). In this study, no effects relevant for classification in regards to specific target organ toxicity following repeated exposure have been observed. A detailed summary of the study is not provided, since a 90-day repeated dose toxicity study is not required for the registered tonnage band of 10-100 tpa. Under consideration of the above data, CAS 102-06-7 is not classified for STOT RE in Annex VI to Regulation (EC) No 1272/2008 (CLP)..Thus, the test item does also not require classification for specific target organ toxicity after repeated exposure according to Regulation (EC) No 1272/2008 (CLP), as amended for the tenth time in Regulation (EU) No 2017/776.