Bis(glycinato-N,O)zinc

Endpoint summary

Description of key information

LD50 value for Plexomin® Zn (Zincbislysinate) is  2000 mg/kg following single-dose intragastric administration to male and female rats. Study according to OECD guideline 425, observation period 14 days, read-across

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2019-08-07 to 2019-09-24

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 425 (Acute Oral Toxicity: Up-and-Down Procedure)

Version / remarks:

Federal Law No. 61–FZ “On the Circulation of Medicinal Products” of 12 April 2010 (as amended);Federal Law No. 323–FZ “On the Basics of Health Protection of the Citizens in the Russian Federation” of 21 November 2011 (as amended)

GLP compliance:

yes

Test type:

up-and-down procedure

Limit test:

no

Species:

rat

Strain:

not specified

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: NPO House of Pharmacy (inhouse bred)
- Females (if applicable) nulliparous and non-pregnant: yes
- Age at study initiation: 8-12 weeks
- Fasting period before study: 16h
- Housing: individually in standard transparent plastic cages. Wood pellets were used as bedding.
- Diet (e.g. ad libitum): Feed for laboratory animals PK-120-1 prepared in accordance with GOST R50258-92 "Compound Feeds for Laboratory Animals. Specifications” was given ad libitum
- Water (e.g. ad libitum): purified water normalized in respect of organoleptic properties, pH, solids, reducing substances, carbon dioxide, nitrates and nitrites, ammonia, chlorides, sulphates, calcium and heavy metals in accordance with SanPiN 2.1.4.1074-01 "Drinking Water. Hygienic Requirements for the Quality of Water from Centralized Drinking Water Supply Systems. Quality Control". Water in standard drinking bowls with steel nose caps was given ad libitum.
- Acclimation period: 5 days
- Method of randomisation in assigning animals to test and control groups: Randomization was not expected in this study, since dosing occurred in stages and individually. The main criterion for including an animal in the experiment was its body weight.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20-26 °C
- Humidity (%): 30-70%
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From:
No. 2.0-31.05/19 of 31 May 2019
No. 2.0-30.06/19 of 01 July 2019

Route of administration:

oral: gavage

Vehicle:

other: 1% starch solution

Details on oral exposure:

VEHICLE
- Concentration in vehicle: Before administration, suspensions of the test article was prepared with concentrations of ≈ 29.2 mg/ml for 175 mg/kg, ≈ 91.7 mg/ml for 550 mg/kg and 333.3 mg/ml for 2000 mg/kg.
- Amount of vehicle (if gavage): 1.5 mL per 250g rat
- Lot/batch no. (if required): М-3.38/19
MAXIMUM DOSE VOLUME APPLIED: 333.3 mg/mL

CLASS METHOD
- Rationale for the selection of the starting dose:since the test article is presumably a low toxicity substance, 175 mg/kg was selected as the starting dose for a single intragastric administration to one male and one female rat.

Doses:

175, 550, 2000 mg/kg bw

No. of animals per sex per dose:

175 mg/kg bw: 1 animal; 550 mg/kg bw: 4 animal; 2000 mg/kg bw 6 animals

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: On day 1, 2, 7 and 15
- Necropsy of survivors performed: yes
- Clinical signs: daily
- Other examinations performed: other:Clinical examination on day 2, 7, 14 and local tolerance evaluation on day 15

Statistics:

Calculation of LD50 with confidence intervals was performed using the AOT 425 StatPgm program (Westat, USA).

Key result

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 300 - <= 2 000 mg/kg bw

Based on:

act. ingr.

95% CL:

> 864.4 - < 4 210

Mortality:

Following administration of the test article at 2000 mg/kg, 4 male and 4 female rats died. Death was recorded 48 hours after the administration in 58% of animals (4 males and 3 females). Only in one female, death was recorded 2 hours after administration. The immediate cause of death of all animals was acute heart failure.

Clinical signs:

other: Clinical signs of intoxication were recorded in animals treated with a single intragastric dose of Plexomin® Zn 2000 mg/kg, and which were manifested as dyspnoea and wheezing, depressed behaviour with decreased response to external stimuli, ruffled fur an

Gross pathology:

No gross abnormalities in the internal organs were identified at the scheduled necropsy in experimental animals treated with a single intragastric dose, however, during unscheduled necropsy, foci of oedema, emphysema and haemorrhagic impregnation of lung tissue, venous congestion of internal organs, as well as mild and moderate congestion of the brain vessels were found in all animal bodies. The immediate cause of death of the animals was acute heart failure.

Other findings:

The test article Plexomin® Zn following a single-dose intragastric administration had a moderate local irritant effect, which was manifested as catarrhal gastritis in animals when administered at doses of 175 mg/kg (in 1 female) and 550 mg/kg (in 1 male) and as a film of the test article on the gastric mucosa at 2000 mg/kg. The abnormalities identified in the animals that received the test drug at 2000 mg/kg were reversible.

A total of 4 male and 4 female rats died. Animals Nos. 3, 7, 9, 11, 18, 22, 24 and 26 treated with the test article, Plexomin^®Zn 2000 mg/kg, died.

The bodies of all animals that died during the study were subjected to a necropsy and gross examination.

Table 1: Incidence of abnormalities according to the necropsy results of rats treated with the test article (number of animals with identified abnormality/total number of animals)

Organs	Abnormalities identified	Plexomin^®Zn feed additive (Phytobiotics Futterzusatzstoffe GmbH, Germany)
		2000 mg/kg
		males	females
Lungs	Foci of emphysema, oedema and haemorrhagic impregnation of the tissue	4/4	4/4
Internal organs	Venous congestion	4/4	4/4
Brain	Oedema and vascular congestion	4/4	4/4

The necropsy of animals subjected to a scheduled euthanasia did not find any abnormalities in the internal organs following single intragastric doses of the test article, Plexomin^®Zn of 175 mg/kg, 550 mg/kg and 2000 mg/kg.

Interpretation of results:

Category 4 based on GHS criteria

Conclusions:

The LD50 value for the test item is >300 and < 2000 mg/kg following single-dose intragastric administration to male and female rats. The test item can be classified as toxicity category 4 according to the international GHS classification.

Executive summary:

In an acute oral toxicity study according to OECD Guideline 425, groups of male and female Sprague-Dawley rats, 8-12 weeks old were given a single oral dose of bis(glycinato-N,O)zinc (% a.i.) in 1% starch solution at doses of  175, 550, or 2000 mg/kg bw and observed for 15 days.

Oral LD50 Combined [males/females]= >300 and <2000 mg/kg bw (95% C.I. 864.4–4210 mg/kg).

Bis(glycinato-N,O)zincis of low toxicity based on the LD50 in both female and male rats.

The first symptoms were observed 5 minutes after administration in 67% of male and female rats that received the test item at 2000 mg/kg. The toxic effect was manifested as dyspnoea and wheezing, depressed behaviour. Ruffled fur and decreased response to picking up and sound stimuli (a clap) were noted in these animals 30 minutes after administration. Forced lying on the stomachs was also noted in one male and female. The female rat developed diarrhoea 30 minutes after administration. Another female rat treated with the test substance at 2000 mg/kg developed ataxia 3 hours after administration, which was manifested as incoordination and bouncing when moving. Symptoms of intoxication persisted in animals until death, which was recorded in 58% of animals 48 hours after administration. Only in one female, death was recorded 2 hours after administration. The immediate cause of death of all animals was acute heart failure. The animals that received the test substance at doses of 175 mg/kg and 550 mg/kg exhibited no symptoms of intoxication.

In two males and females which received the test item at 2000 mg/kg, signs of intoxication were observed 1 to 2 hours after administration, which were manifested as depressed behaviour and ruffled fur. Also, decreased muscle tone was recorded in another female 2 hours after administration. Symptoms of intoxication were reversible and animal condition improved 24 hours after administration. No changes in body weight gain or body weights were observed in all animals. The data obtained allow concluding that the NOAEL for bis(glycinato-N,O)zinc is < 175 mg/kg following single-dose intragastric administration to rats.

Based on these results, bis(glycinato-N,O)zinc is classified according to the Globally Harmonized System for Classification and Labelling of Chemicals (GHS) as Category 4 'Harmful if swallowed' with respect to acute oral toxicity.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Quality of whole database:

The study was conducted according to OECD guideline 425 under GLP conditions, thus, there are no limitations of the quality of the database.

Acute toxicity: via inhalation route

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

In an acute oral toxicity study (according to OECD 425), groups of male and female Sprague-Dawley rats, 8-12 weeks old were given a single oral dose of Zinc bislysinate (% a.i.) in 1% starch solution at doses of  175, 550, or 2000 mg/kg bw and observed for 15 days. Oral LD50 Combined [males/females]= >300 and <2000 mg/kg bw (95% C.I. 864.4–4210 mg/kg) Zinc bislysinate is of low Toxicity based on the LD50 in both female and male rats The first symptoms were observed 5 minutes after administration in 67% of male and female rats that received the test article at 2000 mg/kg. The toxic effect was manifested as dyspnoea and wheezing, depressed behaviour. Ruffled fur and decreased response to picking up and sound stimuli (a clap) were noted in these animals 30 minutes after administration. Forced lying on the stomachs was also noted in one male and female. The female rat developed diarrhoea 30 minutes after administration. Another female rat treated with the test object at 2000 mg/kg developed ataxia 3 hours after administration, which was manifested as incoordination and bouncing when moving. Symptoms of intoxication persisted in animals until death, which was recorded in 58% of animals 48 hours after administration. Only in female, death was recorded 2 hours after administration. In two males and females who received the test article at 2000 mg/kg, signs of intoxication were observed 1 to 2 hours after administration, which were manifested as depressed behaviour and ruffled fur. Also, decreased muscle tone was recorded in another female 2 hours after administration. Symptoms of intoxication were reversible and animal condition improved 24 hours after administration. No changes in body weight gain or body weights were observed in all animals. The data obtained allow concluding that the NOAEL for Zinc bislysinate is < 175 mg/kg following single-dose intragastric administration to rats.

Based on these results the test item is classified according to the Globally Harmonized System for Classification and Labelling of Chemicals (GHS) as Category 4 'Harmful if swallowed' with respect to acute oral toxicity.