2-phenylpropan-1-ol

Repeated dose toxicity: oral

Administrative data

Endpoint:

sub-chronic toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1981

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Data source

Reference

Reference Type:

publication

Title:

Short-Term Toxicity of 2-Phenylpropan-1-ol (Hydratropic alcohol) in Rats

Author:

I.F. GAUNT, M.G. WRIGHT and R. COTTRELL

Year:

1982

Bibliographic source:

Fd Chem. Toxic. Vol. 20. pp. 519 to 525, 1982

Report date:

1982

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 408 (Repeated Dose 90-Day Oral Toxicity Study in Rodents)

GLP compliance:

no

Remarks:

pre-dates GLP standard

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

2-phenylpropan-1-ol

EC Number:

214-379-7

EC Name:

2-phenylpropan-1-ol

Cas Number:

1123-85-9

Molecular formula:

C9H12O

IUPAC Name:

2-phenylpropan-1-ol

Test material form:

liquid

Specific details on test material used for the study:

2-Phenylpropan-1-ol was supplied by the International Organization of the Flavor Industry, Geneva. The material complied with the following specification: viscous liquid; relative density (d20/20, 1.000-1.006; refractive index (n20/D), 1.5240-1.5280; acid value, max 1; assay, min 95%. Analysis of the sample used gave the following results: relative density (d20/4), 1.0031; refractive index (n20/D), 1.5251; assay (GLC). 99.2%. The sample was stored in closed containers at 4 °C.

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

Animals and diets: Weanling rats were obtained from a specified-pathogen-free colony of the Wistar strain (Olac 1976 Ltd, Bicester, Oxon). They were housed in groups of five of the same sex and treatment, in plastics and stainless-steel grid-floored cages (North Kent Plastic Cages Ltd, Dartford, Kent) suspended on racks with paper for collection of excreta.
The cages were kept in an air-conditioned room and daily measurement of maximum and minimum temperatures showed 91% of the values to be in the 24 ±3 °C range. All of the daily relative humidity measurements were in the 55 ±10% range. The weanling rats were acclimatized to the environmental conditions for 9 days before receiving the test diets.

Administration / exposure

Route of administration:

oral: feed

Details on route of administration:

The rats were divided into four groups of 15 males and 15 females and the dietary concentrations of the test material were adjusted, on the basis of food-intake and body-weight measurements, to provide as nearly as possible a constant intake of 0 (control), 10, 40 and 160 mg 2-phenylpropan-1-ol/kg body weight/day for the four groups throughout the 13-wk feeding period. The basic diet was Laboratory Animal Diet No. 2 (Spratt’s Patent Ltd, Barking, Essex); fresh test diets were prepared at weekly intervals and stored in closed metal containers.

Vehicle:

unchanged (no vehicle)

Remarks:

in feed

Details on oral exposure:

The basic diet, to provide as nearly as possible a constant intake of 0 (control), 10, 40 and 160 mg 2-phenylpropan-1-al/kg body weight/day for the four groups throughout the 13-wk feeding period, was Laboratory Animal Diet No. 2 (Spratt’s Patent Ltd, Barking, Essex); fresh test diets were prepared at weekly intervals and stored in closed metal containers.

Analytical verification of doses or concentrations:

not specified

Duration of treatment / exposure:

13 weeks

Frequency of treatment:

daily via feed

Doses / concentrations

Doses / concentrations 1

Dose / conc.:

0 mg/kg bw/day (actual dose received)

Remarks:

negative control

Doses / concentrations 2

Dose / conc.:

10 mg/kg bw/day (actual dose received)

Remarks:

low dose group

Doses / concentrations 3

Dose / conc.:

40 mg/kg bw/day (actual dose received)

Remarks:

mid dose group

Doses / concentrations 4

Dose / conc.:

160 mg/kg bw/day (actual dose received)

Remarks:

high dose group

No. of animals per sex per dose:

15

Control animals:

yes, plain diet

Examinations

Observations and examinations performed and frequency:

Test procedure: The rats were observed daily for abnormalities of condition. They were weighed initially and then twice weekly throughout the study.
Food and water intakes were recorded for each cage of rats for 3 days before treatment and at twice-weekly intervals during the experiment.
Blood, collected from the retro-orbital sinus at wk 6 and from the aorta during the anaesthetic phase prior to the post-mortem examination, was examined for haemoglobin concentration, erythrocyte count, packed cell volume and leucocyte count. Counts of reticulocytes and the different types of leucocytes were confined to the samples from the control and highest dose groups. Serum was separated from the blood collected at the end of the study and was analysed for glucose, urea, protein, albumin, glutamic-oxalacetic transaminase. glutamic-pyruvic transaminase and lactic dehydrogenase.
Urine was collected over a 6-hr period, from each rat during wk 6 and during the last week of the experiment. It was examined for volume, specific gravity and pH, and semi-quantitative analyses for glucose, blood, bile, ketones and protein were carried out.
Renal concentrating and diluting ability was examined further by measuring the specific gravity and volume of the urine collected during a 2-hr period immediately after a 25-mL/kg oral water load and of that collected during a 4-hr period starting 16 hr after the water load. The number of cells was counted in the samples collected immediately after the water load.

Sacrifice and pathology:

After the feeding period (on days 95-97 for males and days 98, 99 and 102 for females), the animals were fasted overnight, killed by exsanguination under barbiturate anaesthesia and subjected to a post-mortem examination. Any abnormalities were noted and the adrenal glands, brain, caecum (with and without contents), gonads, heart, kidneys. liver, pituitary, spleen, stomach and thyroid were weighed. Samples of these tissues and of urinary bladder, colon, diaphragm, epididymis, eye, Harderian gland, lung, lymph nodes, mammary gland, nerve, oesophagus, pancreas, prostate, rectum, salivary gland, seminal vesicles, skeletal muscle, skin, small intestine, spinal cord, trachea, thymus, uterus and vagina were preserved. Those from the highest dose level and control groups were sectioned and examined microscopically.

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Description (incidence and severity):

All of the animals survived the treatment period and no abnormalities of condition or behaviour were seen.

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, non-treatment-related

Description (incidence and severity):

The group mean body weights showed no consistent or dose-related reductions in the males. Statistically significant deviations from the control occurred during the first 2 wk in the lowest dose group and during days 67-84 in the intermediate dose group. In females, the mean body weights were lower in all the treated groups than in the control group from wk 3, but the differences were not dose related and did not increase markedly with time. For example, the value for the group given 40 mg/kg was 5% lower than the control value at day 21 and 8% lower by day 91.

Food consumption and compound intake (if feeding study):

effects observed, non-treatment-related

Description (incidence and severity):

The mean food intakes of the male treated groups over the period of the study were slightly lower than those of the controls but not in a dose-related manner, the only statistically significant difference being at the intermediate dose. The twice-weekly measurements for this group were generally 5-10% lower than those for the control group, the differences often reaching statistical significance. Most of the food-intake values for the other male groups were within 5% of the control and only scattered statistically significant differences were found. In the females the food intake of the lowest dose level was similar to that of the controls and in the 40mg/kg/day group there were only small, non-significant differences in both the twice-weekly and overall values. The food intake of the highest dose group was lower from wk 4, resulting in a lower overall mean value.

Food efficiency:

no effects observed

Description (incidence and severity):

The range of dietary concentrations used and the resulting average intakes of phenylpropanol-1-ol are shown in Table 1. The values calculated at twice-weekly intervals showed that 96, 92 and 96% of those for the 10-, 40- and 160-mg/kg/day males were within 10% of the desired dosage. For females, the corresponding figures were 88, 88 and 65%.

Water consumption and compound intake (if drinking water study):

effects observed, non-treatment-related

Description (incidence and severity):

The overall water intakes for the males given the two higher dose levels were similar to the control intake, but at the 10-mg/kg/day dose the overall intake was lower. This reflected the values throughout the study, including the pre-treatment period, although generally the differences during the experiment were not statistically significant. The pattern of water intake by the females was different, with higher intakes by all treated groups although there was no dose relationship.

Ophthalmological findings:

not examined

Haematological findings:

effects observed, non-treatment-related

Description (incidence and severity):

There were inconsistent differences in the results of the haematological examinations at wk 6 and 13 (Table 2). The erythrocyte counts were lower than the control counts in the high-dose males at the end of the study, whereas in the corresponding females at wk 6 this same measurement and the haemoglobin concentration were significantly greater than the control values. The data for the intermediate dose levels are not shown in Table 2, but the only statistically significant deviation from the control was a higher erythrocyte count 7.97 x 10⁶/mm³ in the intermediate-dose males at the first examination.

Clinical biochemistry findings:

effects observed, non-treatment-related

Description (incidence and severity):

The results of the renal concentration and dilution tests in the control and highest dose group (Table 4) were similar, as were the results for the lower dose groups and control. The only statistically significant differences were slightly lower mean volumes of the samples collected at 0-2 hr (50 mL) and 16-20 hr (0.4 mL) from the 40-mg/kg/day females at wk 13 and a low specific gravity (1.057) for the samples taken from the low-dose females at 0-6 hr, again at wk 13.

Urinalysis findings:

effects observed, non-treatment-related

Description (incidence and severity):

No urine samples gave reactions for bilirubin or glucose at either wk 6 or wk 13, and only occasional samples gave positive reactions for blood. The incidence of these did not differ significantly between the treated and control groups. There were some differences in the incidences of samples with various reactions for protein (Table 3). Significantly more samples from the males given 40 mg/kg/day for 6 wk showed an intermediate (+ +) reaction with an associated decrease in the number of samples giving the higher-grade reactions. In the females there were more samples with the minimal grade of reaction from the lowest dose group at wk 13 and from the 160-mg/kg/day group at wk 6. Further statistical analysis of the latter group revealed that the total incidence of animals giving the higher grades of reaction for protein (+ + or greater) was significantly less than the control incidence. The mean pH values for the urines of both sexes given 160 mg phenylpropanol/kg/day were significantly lower than the control values at wk 6, but the difference was much less marked after 13 wk (Table 4). There was no similar finding at the intermediate dose level (pH 7.2 and 6.4 in males and females, respectively, at wk 6). The urinary cell count was slightly higher in the top-dose female group than in the controls at wk 6 and markedly higher at wk 13. However, the latter count was due entirely to one animal with a value of 27.5 x 10³/hr, and when this was excluded the group mean was 0.5 x 10³ cells/hr, close to that for the controls.

Behaviour (functional findings):

no effects observed

Immunological findings:

not examined

Description (incidence and severity):

There were no statistically valid differences between the control and high-dose rats in the results of the serum analyses. With the lower doses, the only statistically significant differences were slightly higher protein concentrations in the males of both groups and a lower concentration of albumin in the low-dose females (Table 5).

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

The relative liver weights of both sexes given 160 mg/kg/day were higher than those of the controls (Table 6). The actual weights were also higher than the controls but the difference was statistically significant only in the males. The same group of males had absolute and relative kidney weights approximately 15% higher than the control values, whilst at the intermediate dose level (40 mg/kg/day) the relative kidney weight was approximately 7% higher than the control with no significant difference in the absolute weight. The absolute and relative kidney weights of the high-dose females were 13-15% higher than those of the control group. These differences were not statistically significant and were due to very high values from one animal. Exclusion of these weights resulted in mean values within 5% of the control.
The males on the intermediate dose level showed higher relative heart and pituitary weights with no significant increase in the absolute weights. These values showed statistical significance by the t-test but there was no overall significance using the analysis of variance involving all the groups. Comparison with the controls showed a higher mean relative caecal weight in the high-dose females, a high relative adrenal weight in the low-dose females, and a high relative brain weight in all the female groups (but showing no dose relationship). None of these findings were associated with a significant difference in the absolute weights.

Gross pathological findings:

effects observed, non-treatment-related

Description (incidence and severity):

The range and severity of the histological findings were similar in the control and high-dose animals and were those to be expected in these animals. Increases in the incidence of lesions were confined to the lung; there were more treated females with peribronchial mononuclear cell cuffing (eight affected compared with two controls) and in the males the incidence of moderate alveolar thickening was higher in the treated group (in ten rats compared with three controls), although the total incidence of treated animals with any grade of alveolar thickening was not significantly increased over that of the controls (15 versus 10).
The female high-dose animal with a high kidney weight proved to have a mesenchymal tumour in the kidney. Other findings in the renal system of this rat were severe nephrosis, chronic inflammatory-cell infiltration and pelvic epithelial hyperplasia, together with hyperplasia of the urinary bladder.
This animal had also shown other signs of renal abnormality in the form of a high serum-urea concentration (22mM compared with a control mean of 95 mM), low specific gravity and high urine volumes in the concentration tests and a high urinary pH and cell count (8.0 and 275, respectively, compared with control means of 6.4 and 0.5). It also showed a strong reaction for blood in the urine at wk 13.

Neuropathological findings:

not examined

Histopathological findings: non-neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

The range and severity of the histological findings were similar in the control and high-dose animals and were those to be expected in these animals. Increases in the incidence of lesions were confined to the lung; there were more treated females with peribronchial mononuclear cell cuffing (eight affected compared with two controls) and in the males the incidence of moderate alveolar thickening was higher in the treated group (in ten rats compared with three controls), although the total incidence of treated animals with any grade of alveolar thickening was not significantly increased over that of the controls (15 versus 10).

Other effects:

not specified

Details on results:

The female high-dose animal with a high kidney weight proved to have a mesenchymal tumour in the kidney. Other findings in the renal system of this rat were severe nephrosis, chronic inflammatory-cell infiltration and pelvic epithelial hyperplasia, together with hyperplasia of the urinary bladder. This animal had also shown other signs of renal abnormality in the form of a high serum-urea concentration (22mM compared with a control mean of 95 mM), low specific gravity and high urine volumes in the concentration tests and a high urinary pH and cell count (8.0 and 275, respectively, compared with control means of 6.4 and 0.5). It also showed a strong reaction for blood in the urine at wk 13.
The authors however concluded this being an incidental effect and not treatment related: It was unexpected to find a renal tumour in an animal of this age, especially as spontaneous tumours of the kidney are considered to be rare (Snell, 1967).
Nevertheless, they do occur; a review of 675 rats of each sex used as controls in 3-month studies in these laboratories revealed one kidney tumour (Gaunt, Farmer, Grasso & Gangolli, 1967). Despite this low background incidence, spontaneous mesenchymal tumours of the kidney are predominantly a neoplasm of the young rat, most having been reported in animals under 12 months of age (Hard, 1976). Although the tumour found in the present study was in a rat given 160 mg 2-phenylpropan-1-ol/kg, the absence of signs of renal damage in the other rats suggests that this lesion was not related to treatment.

Effect levels

Dose descriptor:

NOEL

Effect level:

10 mg/kg bw/day (actual dose received)

Based on:

test mat.

Sex:

male/female

Basis for effect level:

organ weights and organ / body weight ratios

Target system / organ toxicity

Critical effects observed:

no

Organ:

kidney

liver

Applicant's summary and conclusion

Conclusions:

This subchronic oral toxicity study has revealed few effects that can be definitely attributed to treatment. The liver- and kidney-weight increases are considered to be treatment-related, although it is uncertain whether these were toxic or adaptive effects. On this basis the no-effect level for this study was 10 mg/kg/day.

Executive summary:

This subchronic oral toxicity study, dosed via feed at concentrations of 10, 40 and 160 mg/kg bw/day, has revealed few effects that can be definitely attributed to treatment. The liver- and kidney-weight increases are considered to be treatment-related, although it is uncertain whether these were toxic or adaptive effects. Hence, clear adverse effects were not identified in this study and the authors, on this basis, have set the no-effect level (NOEL) for this study to 10 mg/kg/day.