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Description of key information

Repeated dose toxicity: Inhalation

2 weeks repeated dose toxicity study was performed using rats for the test compound chloral upon repeated exposure by inhalation route. The test compound was exposed to vapours of chloral at dose levels of 0 or 0.08 mg/L air to 20 male albino rats of Sprague Dawley strain. Inhalation exposure was were 4 hrs/day, 5 days/week for two week period. The animal were observed for mortality, any reactions displayed and body weight changes. Half of the rats frem each group were sacrificed within a few hours after last inhalation exposure and the remaining half were sacrificed after two weeks recovery period. The animals were subjected to gross and histopathology and organ weights were recorded and subjected to statistical analysis. Six rats died during the two week exposure period and body weight losses were observed in all surviving animals. The animals showed untoward behavioral signs including sneezing, ptosis, dyspnea and weakness. The rats that died during the 2 weeks treatment period displayed severe edema and severe diffuse red discolouration of the lungs. Animals also exhibited reduced organ sizes and empty gastrointestinal tract. Animals surviving the 2 week treatment period and 2 week recovery period displayed white foci on lungs with no occurrences on red discolouration. No treatment related histopathological observation could be observed during the study. Statistical analyses of organ weights revealed several differences between control and treated animals. Lungs, spleen, liver, kidneys, heart and gonads were affected during chloral treatment. On the basis of observation made, the ow observed adverse effect concentration (LOAEC) for chloral is found to be 0.08 mg/L when exposed to male albino rats of Sprague Dawley strain for 14 days.

Key value for chemical safety assessment

Repeated dose toxicity: via oral route - systemic effects

Endpoint conclusion
Endpoint conclusion:
no study available

Repeated dose toxicity: inhalation - systemic effects

Link to relevant study records
Reference
Endpoint:
short-term repeated dose toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
secondary literature
Justification for type of information:
Data is from NTRL report
Qualifier:
according to
Guideline:
other: Refer below principle
Principles of method if other than guideline:
2 weeks repeated dose toxicity study was performed using rats for the test compoun chloral uon repeated exposure by inhalation route
GLP compliance:
not specified
Limit test:
no
Specific details on test material used for the study:
- Name of test material: Chloral anhydrous
- IUPAC name: trichloroacetaldehyde
- Molecular formula: C2HCl3O
- Molecular weight: 147.3879 g/mol
- Substance type: Organic
- Physical state: No data
- Purity: No data
- Impurities: No data
Species:
rat
Strain:
Sprague-Dawley
Remarks:
Albino
Details on species / strain selection:
No data
Sex:
male
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: ARS/ Sprague Dawley, Madison, Wisconsin
- Females (if applicable) nulliparous and non-pregnant: Not applicable
- Age at study initiation: Young rats were used for the study
- Weight at study initiation: No data
- Fasting period before study: No data
- Housing: In stock cages
- Diet (e.g. ad libitum): Standard laboratory diet (Purina rat chow, Ralston Purina Co., St. Louis, Missouri) ad libitum
- Water (e.g. ad libitum): Water ad libitum
- Acclimation period: 5 days

DETAILS OF FOOD AND WATER QUALITY:
Food quality: Standard laboratory diet (Purina rat chow, Ralston Purina Co., St. Louis, Missouri) ad libitum

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: To: Nov 06, 1972 - Nov 17, 1972
Route of administration:
inhalation: vapour
Type of inhalation exposure:
whole body
Vehicle:
air
Remarks on MMAD:
No data
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: 700L Plexiglas inhalation chamber
- Method of holding animals in test chamber: No data available
- Source and rate of air:
Sources: Clean dry air (-40 C dewpoint)
Rate of air: No data available
- Method of conditioning air: No data available
- System of generating particulates/aerosols: baffle plates were used
- Temperature, humidity, pressure in air chamber: 29.92 inches Hg pressure and 25 degree C temperature.
- Air flow rate: 0.13 L/min
- Air change rate: No data
- Method of particle size determination: No data available
- Treatment of exhaust air: No data available

TEST ATMOSPHERE
- Brief description of analytical method used: Air flow rate was measured using rotameter connected upstream of generator. The large air flow rate was measured by a hot wire anemometer
- Samples taken from breathing zone: No data available

VEHICLE (if applicable)
- Justification for use and choice of vehicle: Clean dry air
- Composition of vehicle: No data available
- Type and concentration of dispersant aid (if powder): No data available
- Concentration of test material in vehicle: 0 or 0.08 mg/L
- Lot/batch no. of vehicle (if required): No data available
- Purity of vehicle: No data available
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Air flow rate was measured using rotameter connected upstream of generator. The large air flow rate was measured by a hot wire anemometer
Duration of treatment / exposure:
Duration of treatment: 2 weeks (14 days) and 14 days recovery period
No. of exposure: 10 (During the 14 days treatment period)
Frequency of treatment:
4 hrs/day, 5 days/week
Remarks:
0 or 0.08 mg/L air
No. of animals per sex per dose:
Total: 20
0 mg/L air: 10 male rats
0.08 mg/L air: 10 male rats
Control animals:
yes, concurrent vehicle
Details on study design:
- Dose selection rationale: No data
- Rationale for animal assignment (if not random): No data
- Rationale for selecting satellite groups: No data
- Post-exposure recovery period in satellite groups: 2 weeks
- Section schedule rationale (if not random): No data
Positive control:
No data
Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: No data available
- Cage side observations checked in table [No.?] were included. The animals were observed for mortality

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: During the experiment and after for any reactions displayed

BODY WEIGHT: Yes
- Time schedule for examinations: On first day and weekly thereafter

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: No data available
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No data available

FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: No data available

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No data available
- Time schedule for examinations: No data available

OPHTHALMOSCOPIC EXAMINATION: No data available
- Time schedule for examinations: No data available
- Dose groups that were examined: No data available

HAEMATOLOGY: No data available
- Time schedule for collection of blood: No data available
- Anaesthetic used for blood collection: No data available
- Animals fasted: No data available
- How many animals: No data available
- Parameters checked in table [No.?] were examined. No data available

CLINICAL CHEMISTRY: No data available
- Time schedule for collection of blood:
- Animals fasted: No data available
- How many animals: No data available
- Parameters checked in table [No.?] were examined. No data available

URINALYSIS: No data available
- Time schedule for collection of urine:
- Metabolism cages used for collection of urine: No data available
- Animals fasted: No data available
- Parameters checked in table [No.?] were examined. No data available

NEUROBEHAVIOURAL EXAMINATION: No data available
- Time schedule for examinations: No data available
- Dose groups that were examined: No data available
- Battery of functions tested: sensory activity / grip strength / motor activity / other: No data available

OTHER:
Sacrifice and pathology:
GROSS PATHOLOGY: Yes, five rats from each group of animals were sacrificed within a few hours of last inhalation exposure. The remaining animals were sacrificed after 2 week recovery period. Weight of liver, kidenys, spleen, heart, gonads, brain, lungs, thyroid glands and adrenal glands were determined for control and test animals.

HISTOPATHOLOGY: Yes, for microscopic observations, a complete set of tissues and organs were removed and preserved in 10% buffered formalin solution (pH 7.0). Histopathology was performed on adrenal glands, brain, gonads, heart, kidenys, lliver, lung, lymphnodes (cervical, peribronchial, mesentric), spleen, trachea and thyroid gland.
Other examinations:
No data
Statistics:
Analysis of variance and t tests were conducted on the absolute organ weights and on the organ to body weight and organ to brain weight ratios
Clinical signs:
effects observed, treatment-related
Mortality:
mortality observed, treatment-related
Body weight and weight changes:
effects observed, treatment-related
Food consumption and compound intake (if feeding study):
not specified
Food efficiency:
not specified
Water consumption and compound intake (if drinking water study):
not specified
Ophthalmological findings:
not specified
Haematological findings:
not specified
Clinical biochemistry findings:
not specified
Urinalysis findings:
not specified
Behaviour (functional findings):
not specified
Immunological findings:
not specified
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Gross pathological findings:
effects observed, treatment-related
Neuropathological findings:
not specified
Histopathological findings: non-neoplastic:
effects observed, non-treatment-related
Histopathological findings: neoplastic:
not specified
Other effects:
not specified
Details on results:
Clinical signs and mortality:
Mortality:
One test animal died after sixth inhalation exposure, the second death occured during the seventh day. 4 animals at tenth inhalation exposure, 1 was necropsied to ensure one set of fresh tissues for accurate histological examination and three rats were survived two week of test period followed by two week of recovery period.

Clinical signs: Sneezing was observed after 30 minutes. After 60 min, all animals exhibited ptosis and after 90 min few animals showed dyspnea. All these reactions continued with progressive increases in severity with each daily exposures to the chloral vapours until death or extreme weakness ocurred. Normal behaviour was exhibited by the three surviving rats after the last inhalation exposure.

Body weight and weight gain: Body weight of treated animals was lower than the control animals. The three surviving rats gained a considerable amount of weight during the two week observation period but their final weght was still lower than that of the control rats.

Food consumption and compound intake: No data available

Food efficiency: No data available

Water consumption and compound intake: No data available

Opthalmoscopic examination: No data available

Haematology: No data available

Clinical chemistry: No data available

Urinanalysis: No data available

Neurobehaviour: No data available

Organ weights: Most of the organ weight effects were observed due to starvation and were observed in lungs, brain, adrenal glands, gonads, heart, kidneys, liver and spleen. Significant difference was observed in organ weight and organ weight rations in the lungs and adrenal glands of only animals which was sacrificed after the two week of observation.

Gross pathology: A general stunting of growth of all organs of test rats which diied during the test period and those which were sacrificed after the 2 week observation period. Severe edema and severe diffuse red discoloration of the lungs in all the died rats. In treated animal on necropsy no food was found in the gastrointestinal tract. In two week recovery period animals, only white foci on the lungs of each animal was observed. No gross pathology findings were observed in the tissues and organs examined during the interim or final sacrifice.

Histopathology: No changes were attributed by exposure of chemical; all the effects were observed by naturally occurring disease or the method of sacrifice.
Dose descriptor:
LOAEC
Effect level:
0.08 mg/L air
Based on:
test mat.
Sex:
male
Basis for effect level:
clinical signs
mortality
body weight and weight gain
behaviour (functional findings)
organ weights and organ / body weight ratios
gross pathology
Critical effects observed:
not specified

Table: 1 Individual body weight and weight gain data

Group

Individual body weight (g)

Week no:

Two week body weight gain data

Four week body weight gain data

0

1

2

3

Final

Untreated control

150

209

243

-

-

95

-

 

166

224

258

-

-

92

-

 

176

234

263

-

-

87

-

 

150

215

199

-

-

49

-

 

170

228

256

-

-

86

-

 

153

98

156

195

257

3

104

 

169

207

255

290

311

86

142

 

165

225

258

280

310

93

145

 

155

218

250

282

306

95

151

 

164

240

269

304

335

105

171

Test

198

151

137

209

268

-31

100

 

158

155

143

183

255

-15

97

 

176

144

119

-

-

-57

-

 

184

142

-

-

-

-

-

 

168

147

119

-

-

-49

-

 

162

177

141

-

-

-21

-

 

168

178

152

208

262

-16

94

 

167

150

134

-

-

-33

-

 

174

156

113

-

-

-61

-

 

170

155

-

-

-

-

-

 

Table: 2 Mean organ weight and ratio data

Organ: Lungs

Group

Absolute organ weight (g)

Organ/Body weight ratio (g/100g)

Organ/brain weight ration (g/g)

Interim control

1.307

0.538

0.815

Interim test

3.039**

2.520**

1.970**

Final control

1.537

0.505

0.900

Final test

1.980

0.774*

1.175*

* Statistically significant difference at the 95% CI level

** Statistically significant difference at the 99% CI level

 

Organ: Thyroid

Group

Absolute organ weight (g)

Organ/Body weight ratio (g/100g)

Organ/brain weight ration (g/g)

Interim control

0.018

0.008

0.012

Interim test

0.012

0.011

0.008

Final control

0.019

0.006

0.011

Final test

0.018

0.007

0.011

 

Organ: Spleen

Group

Absolute organ weight (g)

Organ/Body weight ratio (g/100g)

Organ/brain weight ration (g/g)

Interim control

0.692

0.282

0.431

Interim test

0.194**

0.160**

0.128**

Final control

0.721

0.238

0.425

Final test

1.184

0.446

0.702

** Statistically significant difference at the 99% CI level

Organ: Liver

Group

Absolute organ weight (g)

Organ/Body weight ratio (g/100g)

Organ/brain weight ration (g/g)

Interim control

0.983

3.929

6.023

Interim test

4.699**

3.908

3.083**

Final control

11.465

3.778

6.752

Final test

10.100

3.889

5.992

** Statistically significant difference at the 99% CI level

Organ: Kidneys

Group

Absolute organ weight (g)

Organ/Body weight ratio (g/100g)

Organ/brain weight ration (g/g)

Interim control

1.985

0.816

1.237

Interim test

1.164**

0.978**

0.770**

Final control

2.319

0.757

1.368

Final test

1.930

0.748

1.145

** Statistically significant difference at the 99% CI level

Organ: Heart

Group

Absolute organ weight (g)

Organ/Body weight ratio (g/100g)

Organ/brain weight ration (g/g)

Interim control

0.811

0.334

0.506

Interim test

0.524**

0.439**

0.346**

Final control

1.045

0.343

0.617

Final test

0.930

0.361

0.552

** Statistically significant difference at the 99% CI level

Organ: Gonads

Group

Absolute organ weight (g)

Organ/Body weight ratio (g/100g)

Organ/brain weight ration (g/g)

Interim control

3.981

1.646

2.485

Interim test

2.127**

1.774

1.402**

Final control

4.435

1.448

2.560

Final test

3.545

1.372

2.103

** Statistically significant difference at the 99% CI level

Organ: Adrenal glands

Group

Absolute organ weight (g)

Organ/Body weight ratio (g/100g)

Organ/brain weight ration (g/g)

Interim control

0.048

0.020

0.031

Interim test

0.056

0.047**

0.037

Final control

0.048

0.016

0.029

Final test

0.057*

0.022*

0.034

* Statistically significant difference at the 95% CI level

** Statistically significant difference at the 99% CI level

Organ: Brain

Group

Absolute organ weight (g)

Organ/Body weight ratio (g/100g)

Interim control

1.603

0.664

Interim test

1.514

1.269**

Final control

1.703

0.561

Final test

1.684

0.655

** Statistically significant difference at the 99% CI level

Conclusions:
The Low observed adverse effect concentration (LOAEC) for chloral is found to be 0.08 mg/L when exposed to male albino rats of Sprague Dawley strain for 14 days.
Executive summary:

2 weeks repeated dose toxicity study was performed using rats for the test compound chloral upon repeated exposure by inhalation route. The test compound was exposed to vapours of chloral at dose levels of 0 or 0.08 mg/L air to 20 male albino rats of Sprague Dawley strain. Inhalation exposure was were 4 hrs/day, 5 days/week for two week period. The animal were observed for mortality, any reactions displayed and body weight changes. Half of the rats frem each group were sacrificed within a few hours after last inhalation exposure and the remaining half were sacrificed after two weeks recovery period. The animals were subjected to gross and histopathology and organ weights were recorded and subjected to statistical analysis. Six rats died during the two week exposure period and body weight losses were observed in all surviving animals. The animals showed untoward behavioral signs including sneezing, ptosis, dyspnea and weakness. The rats that died during the 2 weeks treatment period displayed severe edema and severe diffuse red discolouration of the lungs. Animals also exhibited reduced organ sizes and empty gastrointestinal tract. Animals surviving the 2 week treatment period and 2 week recovery period displayed white foci on lungs with no occurrences on red discolouration. No treatment related histopathological observation could be observed during the study. Statistical analyses of organ weights revealed several differences between control and treated animals. Lungs, spleen, liver, kidneys, heart and gonads were affected during chloral treatment. On the basis of observation made, the ow observed adverse effect concentration (LOAEC) for chloral is found to be 0.08 mg/L when exposed to male albino rats of Sprague Dawley strain for 14 days.

Endpoint conclusion
Endpoint conclusion:
no study available (further information necessary)
Dose descriptor:
LOAEC
80 mg/m³
Study duration:
subacute
Species:
rat
Quality of whole database:
Data is from K4 NTRL report

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

Repeated dose toxicity: Inhalation

Data available for the target chemical was reviewed to determine the toxic nature of Chloral (IUPAC name: Trichloroacetaldehyde) upon repeated exposure by inhalation route. The studies are as summrized below:

2 weeks repeated dose toxicity study was performed using rats for the test compound chloral upon repeated exposure by inhalation route. The test compound was exposed to vapours of chloral at dose levels of 0 or 0.08 mg/L air to 20 male albino rats of Sprague Dawley strain. Inhalation exposure was were 4 hrs/day, 5 days/week for two week period. The animal were observed for mortality, any reactions displayed and body weight changes. Half of the rats frem each group were sacrificed within a few hours after last inhalation exposure and the remaining half were sacrificed after two weeks recovery period. The animals were subjected to gross and histopathology and organ weights were recorded and subjected to statistical analysis. Six rats died during the two week exposure period and body weight losses were observed in all surviving animals. The animals showed untoward behavioral signs including sneezing, ptosis, dyspnea and weakness. The rats that died during the 2 weeks treatment period displayed severe edema and severe diffuse red discolouration of the lungs. Animals also exhibited reduced organ sizes and empty gastrointestinal tract. Animals surviving the 2 week treatment period and 2 week recovery period displayed white foci on lungs with no occurrences on red discolouration. No treatment related histopathological observation could be observed during the study. Statistical analyses of organ weights revealed several differences between control and treated animals. Lungs, spleen, liver, kidneys, heart and gonads were affected during chloral treatment. On the basis of observation made, the ow observed adverse effect concentration (LOAEC) for chloral is found to be 0.08 mg/L when exposed to male albino rats of Sprague Dawley strain for 14 days.

In another NTRL report, Subacute inhalation toxicity study was performed for Chloral to determine its toxic nature upon repeated exposure. The study was performed on 10 rats for 13 days repeated exposure. The animals were exposed 2 hours daily to the test chemical at dose level of 0 or 12.5 mg/L avg. (11.2, 11.3, 10.4, 10.6, 13.6, 14.5, 11.8, 12.1, 14.2, 13.4, 13.2, 12.5, 14.3 from day 1 to day 13). The rats were observed for mortality, body weight changes, gross and histo- pathology. Seven out of 10 rats died during the 13 days study period due to acute pulmonary edema. No gross pathological signs were noted other than deposition of hemosiderin in the spleen of one rat, congestion in the liver of one rat and in the kidneys of two other rats was observed. During exposure days(treatment days) loss of 10-14% weight was observed with a 5 to 6% gain in weight during the rest period. Based on the observations made, the Low Observed Adverse Effect Concentration (LOAEC) for chloral in rats during 13 days repeated exposure is considered to be avg. 12.5 mg/L.

Subchronic inhalation toxicity study was performed for Chloral to determine its toxic nature upon repeated exposure to dog. The dog was was exposed for 5 weeks from a minimum of 3.1 mg/L to a maximum of 45 mg/L. The exposure was once a week for first three weeks and then 2 hrs/day, 5 days/week for week 4 and week 5. The dog was observed for clinical signs, hematological and urinary changes, gross and histopathology. The dog survived the treatment period. The dog survived the treatment period. No clinical signs of pulmonary edema were noted but the respiratory rate was 36/min suggesting the possible involvment of lungs during week 1. The blood pressure readings taken immediately after the dog was removed from the chamber were not abnormal but both morning and afternoon readings the day following exposure were abnormal. During the week 2, the dog exhibited clinical signs of pulmonary edema upon removal from the inhalation chamber. A watery discharge came from the nose (not edemafluid) and lacrimation was excessive. The dog exhibited labored and noisy respirations and had a high respiration rate of 40-44. The dog tolerated the concentration well during week 3 and there was no respiratory disturbance or increase in the respiratory rate. The dog exhibited irritation of the nose and upper respiratory passages and no dratic effects on circulation was noted during week 4 and 5. An appreciable increase in the RBC over the control values was observed without a corresponding rise in hemoglobin. Differential or little change in WBC count was also noted. A rise in blood platelet count was not observed due to the pulmonary edema produced. Examination of urine did not reveal any abnormality of the excretory function of the kidneys. No gross pathological findings were observed and no damage to the urinary tract was noted due to  inhalation of chloral. No microscopic observations were noted. The Low Observed Adverse Effect Concentration (LOAEC) for chloral in rats by repeated exposure by inhalation route is considered to be 31 mg/L.

The studies available for repeated dose inhalation toxicity study are all performed using a single dose for repeated exposure. Hence it is difficult to judge the toxic nature of chloral upon repeated exposure by inhalation route. Also further testing needs to be done to support the nature of chloral upon repeated exposure by inhalation route. Hence the test chemical is considered to be non - toxic upon repeated exposure by inhalation route.

Justification for classification or non-classification

The studies available for repeated dose inhalation toxicity study are all performed using a single dose for repeated exposure. Hence it is difficult to judge the toxic nature of chloral upon repeated exposure by inhalation route. Also further testing needs to be done to support the nature of chloral upon repeated exposure by inhalation route. Hence the test chemical is considered to be non - toxic upon repeated exposure by inhalation route.