Phenol

Acute Toxicity: oral

Administrative data

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: The study is comparable to OECD Guideline 401 with acceptable restrictions (post exposure observation period 7 days, no necropsy and body weight data; unusual oral application)

Data source

Reference

Reference Type:

publication

Title:

Phenol Studies VI: The acute and comparative toxicity of phenol and o-, m-, and p-cresols for experimental animals

Author:

Deichmann WM, Witherup S

Year:

1944

Bibliographic source:

J Pharmacol Exp Ther 80: 233-240

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

Deviations:

yes

Remarks:

(post exposure observation period 7 days, no necropsy)

GLP compliance:

not specified

Test type:

standard acute method

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Phenol

EC Number:

203-632-7

EC Name:

Phenol

Cas Number:

108-95-2

Molecular formula:

C6H6O

IUPAC Name:

phenol

Details on test material:

reagent grade
Source: Merck
No further details

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

Source Wistar Institute but reared in conducting laboratory; food and water ad libitum.
No further data.

Administration / exposure

Route of administration:

oral: gavage

Details on oral exposure:

Test solution injected directly by a syringe into the oesophagus using a blunt hypodermic needle traversing the esophagus if the volume is <= 1ml; presumably gavage used for higher volume; post exposure observation period not clearly stated but presumably 7 days; different amounts of aqueous preparations containing 2, 5, 10 and 20% of phenol were administered to 5-15 rats per dose group (equal numbers of males and females).

Doses:

300-800 mg/kg bw (see Table below)

No. of animals per sex per dose:

5-15 (equal number of males and females in each group); see also Table below.

Control animals:

no

Details on study design:

Further details see Table below.

Statistics:

No data

Results and discussion

Effect levels

Effect levels 1

Sex:

male/female

Dose descriptor:

LD50

Effect level:

530 mg/kg bw

Remarks on result:

other: 2 & 5% solution

Effect levels 2

Sex:

male/female

Dose descriptor:

LD50

Effect level:

540 mg/kg bw

Remarks on result:

other: 10% solution

Effect levels 3

Sex:

male/female

Dose descriptor:

LD50

Effect level:

340 mg/kg bw

Remarks on result:

other: 20% emulsion

Mortality:

All rats died within 3 to 150 minutes.(see Table below)

Clinical signs:

other: Twitching in eye muscles and those of eyelids and ears, then all over the body (extremities being the last); fluctuating body temperature (mostly subnormal), pulse and respiration rate increased and then became slow, irregular and weak; pupils first cont

Gross pathology:

No data

Any other information on results incl. tables

Oral toxicity in rats in relation to the concentration of aqueous phenol solution

Dose in mg/kg bw (number of rats)	Mortality (in %)	Time till death in minutes
2% Phenol in water (LD50 = 530 mg/kg bw)
400	1/5 (20)	25
500	4/10 (40)	15-150
600	7/10 (70)	19-50
700	8/10 (80)	14-60
800	10/10 (100)	10-90
5% Phenol in water (LD50 = 530 mg/kg bw)
400	1/15 (7)	20
500	6/15 (40)	10-30
600	11/15 (73)	3-80
700	9/10 (90)	4-50
10% Phenol in water (LD50 = 540 mg/kg bw)
500	4/10 (40)	15-35
600	6/10 (60)	10-50
700	9/10 (90)	10-120
800	9/10 (90)	7-60
20% Phenol in water (LD50 = 340 mg/kg bw)
300	6/15 (40)	5-45
400	9/15 (60)	15-60
500	15/15 (100)	5-55

Applicant's summary and conclusion

Conclusions:

After acute oral application in rats the LD50 varied between 340 and 540 mg/kg bw.

Executive summary:

The study is comparable to OECD Guideline 401 with acceptable restrictions (post exposure observation period 7 days, no necropsy and body weight data; unusual oral administration at application volumes <=1 ml).

Different amounts of aqueous solutions/emulsions containing 2, 5, 10 or 20% of phenol were orally administered to 5 -15 rats per dose group (equal numbers of males and females in each group). Phenol concentrations of 2, 5 or 10% resulted in the same degree of toxicity, the LD50 being 530, 530 or 540 mg/kg bw, respectively. The 20% emulsion was somewhat more toxic, the corresponding LD50 being 340 mg/kg bw. All of the animals that died within the study were found dead within 3 to 150 minutes. Clinical signs were twitching in muscles (starting with eye muscles), hypothermia, altered pulse and respiration rate (increased and later slow, irregular and weak), pupils first contracted and later on dilated, salivation, marked dyspnea, tremor and convulsions before death.

Conclusion: After acute oral application in rats the LD50 varied between 340 and 540 mg/kg bw.