Reaction mass of lithium 3-hydroxy-2,2,4-trimethylpentanoate and lithium isobutyrate and sodium 3-hydroxy-2,2,4-trimethylpentanoate and sodium isobutyrate

Endpoint summary

Description of key information

The acute oral toxicity of the Reaction mass of lithium 3-hydroxy-2,2,4-trimethylpentanoate and lithium isobutyrate and sodium 3-hydroxy-2,2,4-trimethylpentanoate and sodium isobutyrate is low. The oral LD50 of the substance was determined to be > 2000 mg/kg bw in an acute oral toxicity study conducted in rats using the Acute Toxic Class Method according to OECD Test Guideline 423 (Matting, 2013). A waiver is proposed for acute dermal toxicity on scientific grounds and for reasons of animal welfare: low acute dermal toxicity is predicted based on available information. A waiver is proposed in accordance with Column 2 of Annex VIII of the REACH Regulation for acute inhalation toxicity on the basis that acute toxicity data are available for the oral route and acute dermal toxicity is similarly predicted to be low.  Inhalation is not predicted to be a significant route of exposure based on the physicochemical properties of the substance.

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:

9 May 2013 to 24 May 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline and GLP compliant study with no deviations affecting study integrity

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: CRL:WI Wistar rats from Charles River Laboratories, Research Models and Services, Germany GmbH, Sandhofer Weg 7, D-97633 Sulzfeld
- Age at study initiation: 8 weeks
- Weight at study initiation: 184-199g
- Fasting period before study: Overnight prior to dosing and up to 3 hours post dosing
- Housing: Group housing, 3 per cage, in Type II polypropylene/polycarbonate cages
- Diet (e.g. ad libitum):ssniff® SM R/M "Autoclavable complete diet for rats and mice – breeding and maintenance - available ad libitum produced by ssniff Spezialdiäten GmbH, D-59494 Soest Germany
- Water (e.g. ad libitum): municapal supply tap water ad libitum
- Acclimation period: 9 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C):20.4 – 25.0 °C
- Humidity (%):35 – 70 %
- Air changes (per hr):15 – 20 air exchanges/hour
- Photoperiod (hrs dark / hrs light):12 hours daily, from 6.00 a.m. to 6.00 p.m.

IN-LIFE DATES: From: 9 May 2013 To: 24 May 2013

Route of administration:

oral: gavage

Vehicle:

water

Remarks:

distilled

Details on oral exposure:

VEHICLE
- Concentration in vehicle: 200 mg/mL
- Amount of vehicle (if gavage): 10 mL/kg bw

MAXIMUM DOSE VOLUME APPLIED: 10 mL/kg bw

DOSAGE PREPARATION (if unusual): The formulation was freshly prepared at a concentration of 200 mg/mL and stirred continuous until dosing was completed

CLASS METHOD (if applicable)
- Rationale for the selection of the starting dose:The initial dose level was selected by the study director to be that which is most likely to produce mortality in some of the dosed animals. In the lack of any preliminary toxicological information, 2000 mg/kg bw was selected to be the starting dose. an initial group of three females was treated at this dose followed by a second group of three females similarly dosed.

Doses:

2000 mg/kg bw

No. of animals per sex per dose:

3 females per group, two groups treated.

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Daily observations and weekly bodyweight recording. Additional clinical observations recorded on Day 1, 30 mins, 1, 2, 3, 4 and 6 hours post administration
- Necropsy of survivors performed: yes

Statistics:

Not applicable for a limit test

Preliminary study:

Not applicable

Sex:

male/female

Dose descriptor:

approximate LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Remarks on result:

other: Based on the acute Toxic Class Method, the median lethal dose was estimated to exceed the highest dose level administered, in the absence of any mortality or signs of toxicity at 2000 mg/kg bw

Mortality:

There were no deaths in either group dosed at 2000 mg/kg bw

Clinical signs:

other: Clinical signs of treatment were observed on Day 1 only - 3/6 rats showed decreased activity; 5/6 developed a hunched back and 2/6 had evidence of pilo-erection but all animals were overtly symptom free within 24 hours of dose administration

Gross pathology:

No macroscopic abnormalities were observed during necropsy of all surviving rats at termination on Day 14

Other findings:

No other findings

Bodyweights

Group	Animal Number	Bodyweight (g) on Day				Bodyweight gain (g)
		-1	0	7	14	-1 to 0	0 to 7	7 to 14	overall
1	1137	214	199	232	247	-15	33	15	33
	1138	210	197	237	243	-13	40	6	33
	1139	212	192	214	250	-20	22	36	38
2	1140	200	184	209	222	-16	25	13	22
	1141	195	186	213	223	-9	27	10	28
	1142	211	194	232	253	-17	38	21	42
Mean		207.0	192.0	222.8	239.7	-15.0	30.8	16.8	32.7

Interpretation of results:

not classified

Remarks:

Migrated information LD50 greater than 2000 mg/kg bw Criteria used for interpretation of results: EU

Conclusions:

The acute oral LD50 in rats for Sodium Isobutyrate Solution was found to exceed 2000 mg/kg bw in female CRL:(WI) rats.
The study result triggers no classification/labelling according to Regulation (EC) No 1272/2008 (CLP).

Executive summary:

The acute oral toxicity of sodium isobutyrate solution was assessed according to the acute toxic class method (OECD 423 and Commission Regulation (EC) No 440/2008 of 30 May 2008, B.1.Tris) in two groups of female CRL:(WI) rats treated at a dose level of 2000 mg/kg bw. Initially, three females were treated at 2000 mg/kg bw and, as no mortality was observed, a confirmatory group was treated at the same dose level. No mortality was observed in the confirmatory group, therefore no further testing was required according to OECD 423 and Commission Regulation (EC) NO 440/2008 of 30 May 2008, B.1.Tris.

Rats were given a single oral treatment by gavage following overnight fasting. Sodium isobutyrate solution was

formulated in distilled water at a concentration of 200 mg/mL and was dosed in a volume of 10 mL/kg bw. Clinical observations were performed at 30 minutes, 1, 2, 3, 4 and 6 hours after dosing and daily for 14 days thereafter. Body weights were measured on Days -1, 0 and 7 and before necropsy. All animals were subjected to a necropsy and a macroscopic examination. There were no mortalities among the six rats dosed at 2000 mg/kg bw. Various clinical signs were observed on day 1 only - decreased activity affecting 3 rats, hunched back (5 rats) and piloerection (2 rats). All were symptom free within 24 hours of dosing. Bodyweight gains showed no effects of treatment. No macroscopic abnormalities were apparent during necropsy. The acute oral LD50, estimated using the Acute Toxic Class method, was greater than 2000 mg/kg bw and no classification is required for oral toxicity.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

Quality of whole database:

Klimisch score = 1. Study compliant with current test guidelines and GLP.

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Data waiving:

other justification

Justification for data waiving:

other:

Endpoint conclusion

Endpoint conclusion:

no study available

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Acute oral toxicity

The acute oral toxicity of the Reaction mass of lithium 3-hydroxy-2,2,4-trimethylpentanoate and lithium isobutyrate and sodium 3-hydroxy-2,2,4-trimethylpentanoate and sodium isobutyrate is low. The acute oral median lethal dose (LD₅₀) of the substance was determined to be > 2000 mg/kg bw in an acute oral toxicity study conducted in rats according to OECD Test Guideline 423 (Acute Toxic Class method; Matting, 2013). In the study, three female rats were treated with the substance initially at 2000 mg/kg bw, administered as a single oral treatment by oral gavage (Group 1). A confirmatory group (three females) was tested at the same dose level (Group 2).

The test substance, sodium isobutyrate solution was formulated in distilled water at a concentration of 200 mg/L and was dosed in a volume of 10 mL/kg bw. Clinical observations were performed at 30 mins, 1, 2, 3, 4 and 6 hours after dosing and daily for 14 days thereafter. Body weights were measured on Days -1, 0 and 7 and before necropsy. All animals were subjected to a necropsy and a macroscopic examination. Various clinical signs were observed on day 1 only - decreased activity affecting 3/6 rats, hunched back (5/6 rats) and piloerection (2/6 rats). All treated rats were symptom free within 24 hours of dosing. Bodyweight gains showed no effects of treatment. No macroscopic abnormalities were apparent during necropsy. No mortality was observed in any of the treated rats, therefore no further testing was required.

Acute dermal toxicity

No acute dermal toxicity studies on the substance are available. A waiver is proposed for this endpoint on scientific grounds and for reasons of animal welfare. No adverse effects or mortalities were seen in an acute oral toxicity study performed with the substance at a limit dose of 2000 mg/kg bw.No mortalities or clinical signs were seen in a skin sensitisation study using the substance.It can therefore be concluded that the substance has low acute toxicity. Dermal absorption of the substance is unlikely to exceed oral absorption and significant differences in the toxicity of the substance due to the route of exposure are not predicted. Testing of the substance is therefore not considered to be scientifically justified and additionally cannot be supported on grounds of animal welfare.

 

Acute inhalation toxicity

A waiver is proposed for acute inhalation toxicity studies in accordance with Column 2 of Annex VIII of the REACH Regulation for this endpoint on the basis that acute toxicity data are available for the oral route and acute dermal toxicity is similarly predicted to be low.  Inhalation is not predicted to be a significant route of exposure based on the physicochemical properties of the substance. The substance is a non-volatile liquid and the use pattern indicates that significant inhalation exposure is unlikely. No additional testing is therefore warranted.

Justification for selection of acute toxicity – oral endpoint
Sole study providing data from a guideline compliant study.

Justification for classification or non-classification

The oral LD₅₀of the Reaction mass of lithium 3-hydroxy-2,2,4-trimethylpentanoate and lithium isobutyrate and sodium 3-hydroxy-2,2,4-trimethylpentanoate and sodium isobutyratein rats is > 2000 mg/kg bw. The substance does not meet the criteria for classification for acute oral toxicity according to Directive 67/548/EEC or Regulation 1272/2008/EC.