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Toxicological information

Repeated dose toxicity: dermal

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Administrative data

Endpoint:
sub-chronic toxicity: dermal
Type of information:
experimental study
Adequacy of study:
key study
Study period:
13 December 1979 to 20 July 1980
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Organ weight measurements and histopathological examinations were performed with limited organs, but the study was conducted under GLP and in accordance with FDA guideline.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1980
Report Date:
1980

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: US FDA
GLP compliance:
yes
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: liquid
Details on test material:
- Name of test material (as cited in study report): Hexyl Cinnamic Aldehyde (HCA)
- Physical state: liquid
- Lot/batch No.: 262
- Storage condition of test material: Room temperature

The registered substance is Amyl cinnamic aldehyde ( 2-benzylideneheptanal; EC number :204-541-5; CAS Number: 122-40-7)

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Camm Research Institute Inc.
- Age at study initiation: 40-50 days
- Weight at study initiation: 225-290 g (males), 170-230 g (females)
- Fasting period before study: Not applicable
- Housing: individually in metalic cages of conventional design
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: 2 weeks


ENVIRONMENTAL CONDITIONS
- Temperature (°C): Not reported
- Humidity (%): Not reported
- Air changes (per hr): Not reported
- Photoperiod (hrs dark / hrs light): Not reported


IN-LIFE DATES: From: 1979-12-13 To: 1980-3-20

Administration / exposure

Type of coverage:
open
Vehicle:
unchanged (no vehicle)
Details on exposure:
TEST SITE
- Area of exposure: Not reported
- Type of wrap if used: Not applicable
- Time intervals for shavings or clipplings: every three days or as needed during the treatment period

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): volume
- Concentration (if solution): not diluted
- Constant volume or concentration used: administered by volume using specific gravity (1.0 at 20 degrees)

Analytical verification of doses or concentrations:
not specified
Duration of treatment / exposure:
90 days
Frequency of treatment:
Daily, 7 days per week
Doses / concentrations
Remarks:
Doses / Concentrations:
0, 125, 250, 500, 1000 mg/kg bw/d
Basis:
nominal per unit body weight
No. of animals per sex per dose:
Group 1 (cage control) consisted of 30 males and 30 females. Each of test substance groups (2-5) consisted of 15 males and 15 females.
Control animals:
yes, concurrent no treatment
Details on study design:
- Dose selection rationale: based on the result of a range finding (28 day) percutaneous toxicity study
- Rationale for animal assignment (if not random): randomly assigned
- Rationale for selecting satellite groups: Not applicable
- Post-exposure recovery period in satellite groups: Not applicable
- Section schedule rationale (if not random): Not reported
Positive control:
Not applicable

Examinations

Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: daily

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: a more detailed physical examination was conducted when animals found to be "abnormal" during the daily general examinations.

DERMAL IRRITATION (if dermal study): Yes
- Time schedule for examinations: No details reported

BODY WEIGHT: Yes
- Time schedule for examinations: A weekly mean variance per group will be calculated and statistically analyzed using Student's t test.

FOOD CONSUMPTION:
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes

OPHTHALMOSCOPIC EXAMINATION: Yes
- Time schedule for examinations: Once in the pretreatment period and again after three months of substance administration.
- Dose groups that were examined: all amimals

HAEMATOLOGY: Yes
- Time schedule for collection of blood: week 6 and week 13
- Anaesthetic used for blood collection: Yes (ether anesthesia)
- Animals fasted: Yes
- How many animals: five animals/sex/group

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: week 6 and week 13
- Animals fasted: Yes
- How many animals: five animals/sex/group

URINALYSIS: Yes
- Time schedule for collection of urine: overnight (approximately 16 hours) collection from five rats/sex/group during week 6 and week 13.
- Metabolism cages used for collection of urine: Yes
- Animals fasted: Yes
Sacrifice and pathology:
Microscopic examination was performed the following tissues; skin (treated and untreated), adrenals, brain, heart, kidneys, liver, stomach, lung, bronchi, mesentric lymph node, pituitary, sternum (bone marrow), spinal cord, testes with epididymis, ovaries, spleen, urinary bladder and nerve with muscle. Some organs were indicators of neurotoxicity (spinal cord, nerve with muscle) and immunotoxicity (spleen, bone marrow, lymph nodes)
Statistics:
No information

Results and discussion

Results of examinations

Clinical signs:
effects observed, treatment-related
Dermal irritation:
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):
no effects observed
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
no effects observed
Haematological findings:
effects observed, treatment-related
Clinical biochemistry findings:
effects observed, treatment-related
Urinalysis findings:
no effects observed
Behaviour (functional findings):
not examined
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Gross pathological findings:
not specified
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Histopathological findings: neoplastic:
no effects observed
Details on results:
CLINICAL SIGNS AND MORTALITY:
Percutaneous administration of Hexyl cinnamic aldehyde caused irritation of the treated skin at all dose levels investigated. The irritation was characterized by erythema, cracking, drying and sloughing of the skin and the severity was related to increasing dose. The behavioural changes were most probably a result of conditioning produced by the irritant effect of the test article and the animals' attempts to avoid treatment. Treatment-related deaths occurred only at the high dose level (1.00 g/kg bw/d).

BODY WEIGHT AND WEIGHT GAIN:
Treatment with Hexyl cinnamic aldehyde at 0.50 and 1.00 g/kg bw/d produced statistically significant reductions in the body weights of both sexes in relation to corresponding values in the control group. Although decreases for females treated at 0.125 g/kg bw/d suggested a treatment-related effect, the absence of similar findings among the corresponding males and the intermediate dose female (0.25 g/kg bw/d) made the biological significance of this finding doubtful.

FOOD CONSUMPTION:
A negative effect of treatment with Hexyl cinnamic aldehyde on this parameter could not be demonstrated in the males and some intervals cited indicated an increase in the absolute amount of food consumed in comparison with the corresponding controls. Females treated at 0.25, 0.50 and 1.00 g/kg bw/d revealed increased absolute food consumption during the treatment period. Since the relative food consumption values were significantly increased in both sexes of the treated animals and corresponding body weights were significantly decreased in the 0.50 and 1.00 g/kg bw/d groups, it is evident that the conversion of food consumed into body weight gain was negatively affected by treatment at these dose levels.

OPHTHALMOSCOPIC EXAMINATION:
After three months of Hexyl cinnamic aldehyde administration ophthalmological examinations did not reveal any effect due to treatment. The findings at the preterminal examination were consistent with those that would be expected during an infection with sialodacryoadenitis.

HAEMATOLOGY:
The administration Hexyl cinnamic aldehyde resulted in consistent differences (alteration at both 6 and 13 weeks of treatment) with respect to the following hematological parameters: White blood cell and segmented neutrophil counts - significant elevation in Group 4 and 5 males, respectively. The high dose males revealed significantly reduced lymphocyte counts on both assessment occasions. The Group 2, 3 and 4 females displayed elevated white blood cell counts on both occations while the Group 4 females had consistent segmented neutrophil elevations. Only the Group 3 females displayed significantly reduced lymphocyte counts at both 6 and 13 weeks of administration.

CLINICAL CHEMISTRY:
The administration of Hexyl cinnamic aldehyde resulted in reduced serum glucose values and increased BUN and SAP in both sexed after 13 weeks of treatment.

URINALYSIS:
Examinaton of the urinalysis data did not reveal differences between treated and control rats.

ORGAN WEIGHTS:
Male organ weights were not affected by treatment; the increased relative values resulted from significantly decreased body weights. Among the females, the increase in kidney and liver weights in comparison with the controls, was supported by both absolute and relative data. Therefore treatment with Hexyl cinnamic aldehyde for 90 days resulted in significantly increased liver and kidney weights for the female rats dosed at 0.25, 0.50 and 1.00 g/kg bw/d.

GROSS PATHOLOGY:
Not reported.

HISTOPATHOLOGY: NON-NEOPLASTIC:
Percutaneous administration of Hexyl cinnamic aldehyde at a dose level of 1.00 g/kg bw/d for 90 days produced hepatic hydropic vacuolization and single cell degeneration, splenic lymphoid depletion and fibrosis, focal gastric ulceration and chronic nectotizing dermatitis with acanthosis, hyperkeratosis and sebaceous gland hyperplasia. In addition dose-related incrases in the myeloid-erythroid and decreases in the cell-fat ratios of the bone marrow occurred.

Effect levels

open allclose all
Dose descriptor:
LOAEL
Remarks:
(local effects)
Effect level:
125 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: Local effects (skin irritation) observed at all dose levels
Dose descriptor:
NOAEL
Remarks:
(systemic effects)
Effect level:
125 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
female
Basis for effect level:
other: Based on increased liver and kidney weights at 250 mg/kg bw/d

Target system / organ toxicity

Critical effects observed:
not specified

Any other information on results incl. tables

Body weight change (group mean)

Sex Male Female
Group Number 1 2 3 4 5 1 2 3 4 5
Test Article Control HCA HCA HCA HCA Control HCA HCA HCA HCA
Dosage Level(mg/kg/day) - 125 250 500 1000 - 125 250 500 1000
Number of Animals 30 15 15 15 15 30 15 15 15 15
Body weight (g)                    
Week -1 208,5 207,4 211,3 203,7 205,1 184,8 180,6 182,8 181,5 180,5
Week 0 255,6 252,9 258,8 249,6 251,4 199,9 196,3 199,4 195,8 197,9
Week 1 282,1 279,5 278,8 244.1** 227.9** 215,7 207.7** 209.1* 199.4** 191.5**
Week 2 310,3 311,3 309 276.4** 245.8** 224,1 219,4 224,7 212.3** 199.9**
Week 3 329 328,8 326,6 288.9** 252.1** 232,9 224.5* 232,1 219.1** 205.7**
Week 4 346,2 345,8 346,1 302.5** 267.7** 239,8 232,9 242,1 228.6* 220.4**
Week 5 360,1 355,5 356,2 309.8** 377.1** 246,8 237.9* 247,7 235.7* 221.2**
Week 6 368,8 362,7 358,2 312.5** 274.4** 248,1 237.9* 251,3 235.6** 228**
Week 7 380,2 378,1 371,6 320.6** 279.5** 255,2 245.1* 258,5 239.6** 238.5**
Week 8 389,4 385,8 373,9 324.7** 275.5** 260 248.1* 263,3 246.7* 248.8*
Week 9 398,8 395,4 380 337.1** 297.9** 262,7 252.5* 268,2 255 256,2
Week 10 406,2 402,3 388,3 337.7** 296.8** 265,8 252.7** 271,9 256 257,6
Week 11 412 406,8 393,8 342.5** 301.4** 267,3 256* 273,2 257.9* 257.8*
Week 12 416,2 404,5 391* 341.2** 298.7** 271,8 259.2* 273,2 257.9* 257.8*
Week 13 406,5 396,5 379.1* 332.9** 282** 262,3 250.1* 268,1 255,3 254,3

*P<0.05, **P<0.01

Food consumption

Sex Male Female
Group Number 1 2 3 4 5 1 2 3 4 5
Test Article Control HCA HCA HCA HCA Control HCA HCA HCA HCA
Dosage Level(mg/kg/day) - 125 250 500 1000 - 125 250 500 1000
Number of Animals 30 15 15 15 15 30 15 15 15 15
Food consumption                     
(g/rat/day)     Week -1 23,8 23,3 23,9 23,2 23,5 Data are missing (page 29)
Week 0 24,3 24 23.1* 19.2** 17.8**
Week 1 24,4 25,3 26* 25,4 24,7
Week 2 25 26 27.3** 25,8 25,5
Week 3 25,1 26,3 26,3 25,8 26,3
Week 4 25,2 26 26,3 25,5 24,2
Week 5 24,3 25,5 25,4 24,6 24,2
Week 6 24,2 26.2** 26.8** 25,5 24,7 18,5 19,7 21** 23** 26.1**
Week 7 24,6 26.5** 25,9 25,5 24 18,7 19,4 21.2** 22.6** 24.9**
Week 8 24 26.4** 25,9 25,3 24,4 18,5 19,2 20.8** 21.9** 23.1**
Week 9 24,6 27** 28.3** 26.4* 25,7 19,6 19,9 22.2* 22.7** 26.9**
Week 10 23,3 26.3** 26.4** 26.2** 26.2** 18,4 19,3 21.9** 22.2** 25.5**
Week 11 23,3 25.6** 25.8** 25.4** 26.4** 18,9 19,9 21.3* 22.8** 26.6**
Week 12 21,2 21,6 22,3 24.2* 22 15,7 16,3 18.9** 22.8** 23.7**
Food consumption                    
(g/kg/day)     Week -1 102,4 101,2 101,6 102,4 103 96,6 95,9 97,8 97,6 99,4
Week 0 90,5 90,3 85.7** 77.8** 74** 91,5 92,4 96,5 86.2* 102.2**
Week 1 82,6 85,6 88.5** 97.4** 104.7** 83,1 91.4** 95.2** 101** 122.1**
Week 2 78,2 81.3* 85.6** 91.7** 103** 86,3 94.7** 94.7** 100.1** 158.9**
Week 3 74,4 78* 78.2* 87.4** 102.2** 82 89.4* 90.9** 96.1** 122.3**
Week 4 71,3 74,3 74.9* 83.4** 88.4** 82,9 85,5 89.6* 92.4** 115.9**
Week 5 66,7 71.2* 71.1** 79.1** 88.9** 74,5 80,3 80,8 92.2** 108.3**
Week 6 64,6 71** 73.4** 80.6** 91.1** 73,7 81.5** 82.7** 97.1** 115.4**
Week 7 63,9 69.6** 69.4** 79.3** 86.7** 72,7 78.8* 81.6** 93.1** 103**
Week 8 61 67.9** 68.6** 76.7** 85.2** 70,9 76.7* 78.5* 87.3** 91.8**
Week 9 61,1 67.7** 74.2** 78.3** 86.6** 74,1 78,7 82.3* 89.1** 104.7**
Week 10 57 65** 67.5** 77.1** 87.9** 69 76** 80.2** 86.5** 99.3**
Week 11 56,1 63.3** 65.8** 74.3** 88.4** 70,3 77.3* 77.8* 88.4** 103.6**
Week 12 51,4 54,1 58* 71.8** 75.7** 58,6 64,2 70** 89** 92.9**

*P<0.05, **P<0.01

Hematology

Sex Male Female
Group Number 1 2 3 4 5 1 2 3 4 5
Test Article Control HCA HCA HCA HCA Control HCA HCA HCA HCA
Dosage Level(mg/kg/day) - 125 250 500 1000 - 125 250 500 1000
Number of Animals 30 15 15 15 15 30 15 15 15 15
Hematology                    
Leucocyte(WBC)  6week 8,2 10.1** 11* 14.9** 10,2 6,3 8.5** 9.6** 9** 10.9**
x103 13week 10 13 7,8 11,6 15.3* 6,9 10.5** 11.7** 13** 7,4
Erythrocyte(RBC)   6week 8,06 8.54* 8.47* 8 8.7* 7,71 7,78 7,45 7,84 8.24**
x103 13week 8,69 8,7 8,66 8,76 8,87 7,52 7,56 7.24* 7,84 7,96
Hemoglobin  6week 15,5 16 15,9 15,1 16.4* 15 15 14,8 14,8 15,5
 (g/100ml) 13week 16,2 16,1 16 16,1 16,4 14,7 14,7 13,7 14,6 14,9
Hematocrit  6week 44,2 46,2 45,8 44 48** 42,6 43,6 42,4 43,6 45.8**
(%) 13week 47 47 46,8 47,8 48,6 41,8 41,8 40.6* 42,4 43,4
Neutrophil  6week 14,6 29.6** 28.4** 35.6** 45.8** 13,4 30.8** 21.8** 38.8** 54.4**
 (% of total) 13week 33 45.6* 42 43.6* 52.2** 38,6 44,4 43,4 56.4** 40,6
Lymphocyte 6week 83 66.8** 69.2** 61.6** 52.4** 85 65.2** 75** 58.8** 44.2**
( % of total) 13week 63 51 54,2 52,6 44** 58,6 53 51 40.2** 55,4
Platelet (10) 13week 490,8 392,4 911,8 719** 744,4 629 622,8 436 368 972.8*

*P<0.05, **P<0.01

MCV NT NT NT NT NT NT NT NT NT NT
MCH NT NT NT NT NT NT NT NT NT NT
MCHC NT NT NT NT NT NT NT NT NT NT
Monocyte  (% of total) NT NT NT NT NT NT NT NT NT NT
Eosinophil (% of total) NT NT NT NT NT NT NT NT NT NT
Basophil   (% of total) NT NT NT NT NT NT NT NT NT NT
Nucleated RBC/100WBC NT NT NT NT NT NT NT NT NT NT

NT: not tested, *P<0.05, **P<0.01

Serum Chemistry

Sex Male Female
Group Number 1 2 3 4 5 1 2 3 4 5
Test Article Control HCA HCA HCA HCA Control HCA HCA HCA HCA
Dosage Level(mg/kg/day) - 125 250 500 1000 - 125 250 500 1000
Number of Animals 30 15 15 15 15 30 15 15 15 15
Serum Chemistry                    
Total Bilirubin 6week 0,4 0,4 0.3** 0.3** 0.2** 0,4 0,4 0.3** 0.3** 0.3*
(mg/dl) 13week 0,3 0,3 0,2 0,3 0,3 0,3 0,3 0,3 0.2* 0,3
BUN 6week 16,4 20** 18.4* 24** 32** 17,4 19 19,8 23.2* 25**
(mg/dl) 13week 15,8 16,4 19,6 26** 24.6** 14,6 17.4** 16.4* 17 26.8**
GPT 6week 39,4 42,8 43 50.2** 72.4* 27,4 33** 44.6** 42.8** 48.8**
(IU/L) 13week 46 49,2 54,6 47,4 50,6 34,6 42 40.6** 48.6** 40.6*
GOT 6week 104,2 97,2 96 127 170,6 91,2 93,3 137** 140.4** 129.8**
(IU/L) 13week 162,4 177,6 143 170 177,2 177,8 215,2 233,6 214 149,4
ALP 6week 104,8 144.8** 139.4* 152.2* 211.2** 83,4 108.5** 124.6** 122** 164.6**
(IU/L) 13week 78,6 109** 114,6 146.4** 224.6** 70 105.2** 110.6** 113.8** 164**
Glucose 6week 103,4 94 89.4* 80.2** 77.4** 111,2 91.6** 87.8** 86** 88.4**
(mg/dl) 13week 103,4 101 85.4* 97,4 78** 98,8 96 88.6** 84.4** 84*
LDH (IU/L) 13week 1135,2 984,6 457.8** 1296 909,6 1300,2 969 823,4 1276,8 975,6
CPK(IU/L) 13week 543,4 645,6 159.6* 534,2 389,4 562,6 448,8 667,2 511,6 507,4

*P<0.05, **P<0.01

 Albumin        (g%) NT NT NT NT NT NT NT NT NT NT
 Total Protein   (g%) NT NT NT NT NT NT NT NT NT NT
 Creatinin     NT NT NT NT NT NT NT NT NT NT
 gamma-GTP   NT NT NT NT NT NT NT NT NT NT
 Cholesterol    (mg%) NT NT NT NT NT NT NT NT NT NT
 Calcium       (mg%) NT NT NT NT NT NT NT NT NT NT
 Chloride       NT NT NT NT NT NT NT NT NT NT
 Phosphorus   (mg%) NT NT NT NT NT NT NT NT NT NT
 Potassium      NT NT NT NT NT NT NT NT NT NT
 Sodium  NT NT NT NT NT NT NT NT NT NT

NT: not tested, *P<0.05, **P<0.01

Urinalysis

Sex Male Female
Group Number 1 2 3 4 5 1 2 3 4 5
Test Article Control HCA HCA HCA HCA Control HCA HCA HCA HCA
Dosage Level(mg/kg/day) - 125 250 500 1000 - 125 250 500 1000
Number of Animals 30 15 15 15 15 30 15 15 15 15
Urinalysis - - - - - - - - - -

-: no effect

Ophthalmology

Sex Male Female
Group Number 1 2 3 4 5 1 2 3 4 5
Test Article Control HCA HCA HCA HCA Control HCA HCA HCA HCA
Dosage Level(mg/kg/day) - 125 250 500 1000 - 125 250 500 1000
Number of Animals 30 15 15 15 15 30 15 15 15 15
Ophthalmology - - - - - - - - - -

-: no effect

Organ weight (Absolute)

Sex Male Female
Group Number 1 2 3 4 5 1 2 3 4 5
Test Article Control HCA HCA HCA HCA Control HCA HCA HCA HCA
Dosage Level(mg/kg/day) - 125 250 500 1000 - 125 250 500 1000
Number of Animals 30 15 15 15 15 30 15 15 15 15
Organ weight (Absolute)  
 Brain 1,892 1,877 1,847 1.839* 1.814* 1,795 1,765 1,766 1,788 1,796
 Left Gonad 2,927 2,928 2,951 2.652** 2.394** 0,059 0,054 0,065 0,057 0,059
 Right Gonad 3,01 3,013 2.863* 2.815** 2.465** 0,057 0,051 0,06 0,062 0,054
 Left Kidney 1,551 1,599 1,613 1,562 1.402** 0,943 0,953 1.026** 1.035** 1.08**
 Right Kidney 1,555 1,66 1,593 1,591 1.394** 0,972 0,973 1.072** 1.049* 1.094**
 Liver 12,598 13,431 13,182 12,903 11.004* 7,617 8.19* 9.257** 9.357** 10.475**

*P<0.05, **P<0.01

Organ weight (Relative)

Sex Male Female
Group Number 1 2 3 4 5 1 2 3 4 5
Test Article Control HCA HCA HCA HCA Control HCA HCA HCA HCA
Dosage Level(mg/kg/day) - 125 250 500 1000 - 125 250 500 1000
Number of Animals 30 15 15 15 15 30 15 15 15 15
Organ weight (Relative)  
 Body weight (g) 388,8 380,2 365.8* 319.2** 262.8** 251,9 242.3* 258,7 244,1 237.8*
 Brain 0,488 0,495 0.508* 0.578** 0.696** 0,714 0,732 0,689 0,734 0.758**
 Left Gonad 0,755 0,772 0,809 0.834* 0.917** 0,023 0,023 0,025 0,023 0,025
 Right Gonad 0,776 0,794 0,79 0.883** 0.949** 0,023 0,021 0,023 0,026 0,023
 Left Kidney 0,4 0,419 0.443** 0.489** 0.535** 0,375 0,393 0.397* 0.424** 0.456**
 Right Kidney 0,4 0.435* 0.436** 0.498** 0.534** 0,387 0,402 0.415** 0.43** 0.461**
 Liver 3,234 3.516* 3.609** 4.035** 4.176** 3,018 3.377** 3.577** 3.83** 4.4**

*P<0.05, **P<0.01

Histopathological findings

group Liver Alterations 1) Spleen Alterations 2) Skin Alterations 3) Gastric Ulceration
control 0/60 0/60 0/60 0/60
HCA 1.00 kg/kg 14(male 10, female 4)/30 10(male 6, female 4)/30 30(male 15, female 15)/30 4(male 2, female 2)/30

1) accentuated regeneration; single cell degeneration and hydropic vacuolization

2) lymphoid depletion, fibrosis and hemosiderosis

3) chronic dermatitis with acanthosis, hyperkeratosis and sebaceous hyperplasia

Applicant's summary and conclusion

Conclusions:
Based on the effects observed in this study, a LOAEL of 125 mg/kg bw/d can be set for local effects based on skin irritation and a NOAEL of 125 mg/kg bw/d is proposed for systemic effects; the NOAEL for systemic effects is likely to be a conservative derivation, taking into account that both dermal and oral exposures are likely to have occurred.
Executive summary:

In a sub-chronic toxicity study performed similarly to OECD guideline No. 411, Hexyl cinnamic aldehyde was administered percutaneously to Albino rats (15/sex/doses) at 125, 250, 500 and 1000 mg/kg bw/d for 90 consecutive days. For control purposes, a fifth group containing 30 animals/sex was maintained without treatment.

Percutaneous administration of the test article resulted in dose-dependent dermal irritation characterized by erythema, cracking, dryness and sloughing. Five male and three female rats did not survive 90 days of treatment at 1000 mg/kg bw/d. Body weights (both sexes) were significantly decreased during treatment at the 500 and 1000 mg/kg bw/d dose level. Absolute food consumption (g/rat/day) was increased in females at 250, 500 and 1000 mg/kg bw/d. Although absolute food intake in males was unaffected, both sexes had increased relative values at all dose level. Ophthalmological examination after approximately 13 weeks did not reveal any alteration due to treatment.

Laboratory studies (haematology and clinical biochemistry) demonstrated inconsistent changes in haemoglobin, haematocrit, erythrocyte count, SGOT and SGPT at the six and 13 week sampling occasions. Consistent significant elevations occurred in the white blood cell and the segmented neutrophil counts of the treated Group 4 and 5 males, respectively. However only the high dose males revealed significantly reduced lymphocyte counts on both assessment occasions indicating a differential shift to the left. With respect to the females, Group 2, 3 and 4 displayed elevated white blood cell counts on both occasions, but only the Group 3 females had significantly reduced lymphocyte counts at both 6 and 13 weeks of administration. Clinical biochemistry indicated reduced serum glucose values and increased BUN and SAP in all treated animals after 13 weeks of test article administration. Urinalysis data obtained during the conduct of the study were unremarkable.

Gross examination at necropsy revealed dose-related irritation of the gastrointestinal tract mucosa and the treated skin. The liver and kidney weights of treated females were significantly increased at 250, 500 and 1000 mg/kg bw/d. Histopathological examination revealed morphological alteration at the 1000 mg/kg bw/d dose level in the form of hepatic hydropic vacuolization and single cell degeneration, splenic lymphoid depletion and fibrosis, focal gastric ulceration and chronic necrotizing dermatitis. Bone marrow examination revealed dose-related increase in the myeloid-erythroid and decrease of the cell-fat ratios.

Application of HCA induced cracking and dryness of the skin in all the treated animals. Study authors suggested that the gastrointestinal irritation observed at the highest dose tested was a consequence of HCA intake during grooming and ingestion of necrotic skin. Indeed neither coverage nor restrainers were used to prevent ingestion. Systemic effects observed at this dose are more likely the consequence of HCA ingestion rather than the results of HCA skin application itself. The skin absorption potential of HCA which is estimated to be very low (0.183%) supports this hypothesis.

Based on the observed effects, a LOAEL of 125 mg/kg bw/d can be set for local effects based on skin irritation and a NOAEL of 125 mg/kg bw/d is proposed for systemic effects; the NOAEL for systemic effects is likely to be a conservative derivation, taking into account that both dermal and oral exposures are likely to have occurred.