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Toxicological information

Toxicity to reproduction

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Administrative data

Endpoint:
screening for reproductive / developmental toxicity
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
guideline study without detailed documentation
Remarks:
Study conducted following OECD guideline 421 and GLP principles. However, only limited data were available for review (data from SIDS Initial Assessment Report).
Justification for type of information:
The rationale to read across the data is attached in section 14.
Cross-reference
Reason / purpose:
reference to same study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2005
Report Date:
2005

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 421 (Reproduction / Developmental Toxicity Screening Test)
GLP compliance:
yes
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): TMAH
- Analytical purity: >99.9%
- Lot No.: 40914

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: not reported
- Age at study initiation: (P) 9 wks; (F1) 4 days
No further details provided.

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
water
Details on exposure:
No details reported.
Details on mating procedure:
No details reported.
Analytical verification of doses or concentrations:
not specified
Duration of treatment / exposure:
Male: 14 days before mating to the day before scheduled death through mating (total 32 days).
Female: 14 days before mating to 3 days after delivery through mating and gestation periods.
Frequency of treatment:
daily
Details on study schedule:
No details reported
Doses / concentrationsopen allclose all
Dose / conc.:
1 mg/kg bw/day
Dose / conc.:
5 mg/kg bw/day
Dose / conc.:
20 mg/kg bw/day
No. of animals per sex per dose:
10
Control animals:
yes, concurrent vehicle
Details on study design:
For mating, one male to one female mating was used. A female rat was placed together with a male rat until copulation occurred. When no copulation was observed, the female animal was mated with another male animal of the same dose group for additional 14 days. Day 0 of gestation (GD 0) was defined as the day a vaginal plug or sperm was found.
Positive control:
No

Examinations

Parental animals: Observations and examinations:
CAGE SIDE OBSERVATIONS: Yes

DETAILED CLINICAL OBSERVATIONS: Yes, twice daily

BODY WEIGHT: Yes, males were weighed on Day 1 and 3 of dosing, and weekly thereafter. Females were weighed on Day 1, 3 and 7 of dosing, weekly thereafter until delivery, and PND 0 and 4.
Litter observations:
Clinical signs and body weights of the live pups were recorded.
Postmortem examinations (parental animals):
Autopsy at end of experiment.
Postmortem examinations (offspring):
Autopsy at end of experiment.
Statistics:
Statistical analysis : Bartlett's test, one-way analysis of variance, Dunnett's test, Kruskal-wallis test, chi-square test

Results and discussion

Results: P0 (first parental animals)

General toxicity (P0)

Clinical signs:
effects observed, treatment-related
Description (incidence and severity):
Salivation was observed on the 4th day of administration and later in male and female rats at 5 mg/kg bw/day and higher. Salivation was considered to be due to strong alkaline property of TMAH, but not due to toxic effects of TMAH. In the female animals at 20 mg/kg bw/day, a decrease in locomotor activity, incomplete eyelid opening or eyelid closure, and loss of hair were observed on GD 21 and thereafter.
Mortality:
mortality observed, treatment-related
Description (incidence):
One female rat at 20 mg/kg bw/day died on GD 22 and another one on GD 23 during parturition. Although the two deaths occurred at highest dose level, no further details are included on cause of death. therefore it is unclear if mortality was substance-related or incidental.
Body weight and weight changes:
effects observed, treatment-related
Description (incidence and severity):
Significant decrease in body weight females after parturition.
Organ weight findings including organ / body weight ratios:
not specified
Gross pathological findings:
not specified
Histopathological findings: non-neoplastic:
not specified

Reproductive function / performance (P0)

Reproductive function: oestrous cycle:
not examined
Reproductive function: sperm measures:
not specified
Reproductive performance:
no effects observed
Description (incidence and severity):
Tetramethylammonium hydroxide showed no effect on number of days required for successful copulation, copulation index, fertility indices of males and females, implantation index, gestation length and delivery index.

Effect levels (P0)

open allclose all
Key result
Dose descriptor:
NOAEL
Effect level:
5 mg/kg bw/day (actual dose received)
Based on:
test mat.
Sex:
female
Basis for effect level:
mortality
body weight and weight gain
Key result
Dose descriptor:
NOAEL
Effect level:
>= 20 mg/kg bw/day
Based on:
test mat.
Sex:
male/female
Basis for effect level:
reproductive performance

Results: F1 generation

General toxicity (F1)

Clinical signs:
no effects observed
Mortality / viability:
mortality observed, treatment-related
Description (incidence and severity):
At 20 mg/kg, one stillborn was observed (male). The number of total newborns per dam that delivered newborns was 13.2, 14.0, 13.5 and 12.3 at respectively 0, 1, 5 and 20 mg/kg bw/day.
Body weight and weight changes:
not examined
Sexual maturation:
not examined
Organ weight findings including organ / body weight ratios:
not specified
Gross pathological findings:
not specified
Histopathological findings:
not examined

Developmental neurotoxicity (F1)

Behaviour (functional findings):
not examined

Developmental immunotoxicity (F1)

Developmental immunotoxicity:
not examined

Details on results (F1)

There was no effect of tetramethylammonium hydroxide on either the numbers of total newborns, sex ratio. No compound-related abnormality was observed either in external features. The number of offspring per dam was 13.2, 14, 13.5 and 12.3 for 0, 1, 5 and 20 mg/kg bw respectively.
The percentage of live newborns at day 4 after birth was 97.7%, 98.4%, 100% and 85.4% for 0, 1, 5 and 20 mg/kg bw respectively.

Effect levels (F1)

Key result
Dose descriptor:
NOAEL
Generation:
F1
Effect level:
>= 20 mg/kg bw/day (actual dose received)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: No effects seen at highest test concentration.
Remarks on result:
other: Mortality of pups during day 1-4 after birth was seen at 20 mg/kg bw/day, but in absence of more detailed information this effect is considered to be related to maternal toxicity and not a direct effect of TMAH.

Overall reproductive toxicity

Key result
Reproductive effects observed:
no

Any other information on results incl. tables

Table 1. Mating and fertility findings in the reproductive/developmental toxicity screening test of tetramethylammonium hydroxide.
============================================================
Parameter
                        Dose (mg/kg bw/day)
                          --------------------------------
                            0     1      5     20
-----------------------------------------------------------
[Male]
No. of animals mated
       10    10     10     11
No. of animals that copulated
                           10    10     10     10
No. of animals that produced pregnant female
                           10    10     10     10
-----------------------------------------------------------
[Female]
No. of animals mated
       10    10     10     10
No. of animals that copulated
                           10    10     10     10
No. of pregnant animals
    10    10     10     10
-----------------------------------------------------------
Duration of mating(days required for successful copulation)
 Mean                     3.0   2.7    3.2    4.7
 S.D.                    1.49   1.42   1.03   5.44
============================================================

Table 2. Postnatal outcomes in the reproductive/developmental toxicity screening test of tetramethylammonium hydroxide.
============================================================
Parameter
                    Dose (mg/kg bw/day)
                     ----------------------------------
                      0        1         5       20
-----------------------------------------------------------
[Dam]
No. of dams
          10       10        10         9   
No. of dams delivered live newborns
                     10        9        10         8
Duration of pregnancy(day)
 Mean              22.0      22.0     21.8      22.3
 S.D.              0.00      0.50     0.42      0.46
No. of implantation sites 1)
                 141(14.1) 147(14.7) 148(14.8) 123(13.7)
-----------------------------------------------------------
[Newborns]
No. of newborns
  
 Total 2)       132(13.2) 126(14.0) 135(13.5)  98(12.3)
 Male            61        65        71        45
 Female          71        61        64        52
No. of stillborns
  0         0         0         1(Male)
Sex ratio of live newborns at birth (male/female)
                   61/71     65/61     71/64     44/52
No. of deads
         3         2         0        14
No. of live newborns on PND 4
 Total 3)       129(97.7) 124(98.4) 135(100)  82(85.4)
 Male 3)         58(95.1)  64(98.5)  71(100)   37(84.1)
 Female 3)       71(100)   60(98.4)  64(100)   45(86.5)
============================================================
1) The value in parentheses is the number of implantation sites per dam.
2) The value in parentheses is the number of total newborns per dam delivered live newborns.
3) The value in parentheses is percentage of live newborns at birth.

Table 3. External findings on newborns in the reproductive/developmental toxicity screening test of tetramethylammonium hydroxide.
============================================================
Parameter
                        Dose(mg/kg bw/day)
                      ------------------------------------
                           0      1      5      20
-----------------------------------------------------------
No. of dams
               10      9     10       8
-----------------------------------------------------------
[PND 0]
No. of newborns examined
 132    126    135      82
No. of newborns with abnormalities
                           0      0      0       0
-----------------------------------------------------------
[PND 4]
No. of newborns examined
 129    124    135      82
No. of newborns with abnormalities
                           0      0      0       0
============================================================

Applicant's summary and conclusion

Conclusions:
In a reproductive/developmental toxicity screening test in rats according to OECD guideline 421 and GLP principles, the NOAEL for parental toxicity was found to be 5 mg/kg bw/d. Since no effects were seen on fertility and development, the NOAELs for these endpoint were found to be >=20 mg/kg bw/d.
Executive summary:

A reproductive/developmental toxicity screening test was performed with rats according to OECD guideline 421 and GLP principles. TMAH was dosed by oral gavage at 0, 1, 5 and 20 mg/kg bw/d. A significant decrease in food consumption was observed at 20 mg/kg bw/day on Day 3 in male animals and on gestation day (GD) 20 in female animals. In the female animals at 20 mg/kg bw/day, a decrease in locomotor activity, incomplete eyelid opening or eyelid closure, and loss of hair were observed on GD 21 and thereafter, and a significant decrease in body weight on days 0 and 4 after parturition (PND 0 and 4). One female rat at 20 mg/kg bw/day died on GD 22 and another one on GD 23 during parturition. Tetramethylammonium hydroxide showed no effect on any of the following parental reproductive parameters; days required for successful copulation, copulation index, fertility indices of males and females, implantation index, gestation length and delivery index. There was no effect of tetramethylammonium hydroxide on either the numbers of total newborns, sex ratio. No compound-related abnormality was observed either in external features.

Based on these observations, the NOAEL for parental toxicity was found to be 5 mg/kg bw/day and for reproduction/developmental toxicity >=20 mg/kg bw/day in rats.