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Toxicological information

Repeated dose toxicity: oral

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Administrative data

Endpoint:
short-term repeated dose toxicity: oral
Remarks:
combined repeated dose and reproduction / developmental screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
11-July-2006 - 30-Nov-2007
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP and guideline study
Cross-reference
Reason / purpose for cross-reference:
reference to same study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2007
Report date:
2007

Materials and methods

Test guideline
Qualifier:
according to guideline
Guideline:
OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)
Deviations:
no
GLP compliance:
yes
Remarks:
Dept. of Health, UK
Limit test:
no

Test material

Constituent 1
Chemical structure
Reference substance name:
Mercaptoacetic acid, monoester with propane-1,2,3-triol
EC Number:
250-264-8
EC Name:
Mercaptoacetic acid, monoester with propane-1,2,3-triol
Cas Number:
30618-84-9
Molecular formula:
C5H10O4S
IUPAC Name:
1,3-dihydroxypropan-2-yl 2-sulfanylacetate 2,3-dihydroxypropyl 2-sulfanylacetate
Test material form:
solid - liquid: suspension
Details on test material:
- Name of test material (as cited in study report): Glycerol Thioglycolate 80 %
- Analytical purity: no data

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
male/female
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Charles River (UK) Limited, Margate, Kent.
- Age at study initiation: 8 weeks
- Weight at study initiation: Males: 280 - 379 g; Females: 192 - 260 g
- Housing: All animals were housed in groups of five in polypropylene cages with stainless steel grid floors and tops, suspended over polypropylene trays lined with absorbent paper. During the mating phase, animals were transferred to similar cages on a one male: one female basis.
Following evidence of successful mating, the males were returned to their original cages. Mated females were housed individually during gestation and lactation, in polypropylene cages with solid floors and stainless steel lids, furnished with softwood flakes (Datesand Ltd. Cheshire, UK).
- Diet: Ad libitum
- Water: Ad libitum
- Acclimation period: 28 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 ± 2 °C
- Humidity (%): 55 ± 15 % relative humidity
- Air changes (per hr): 15 x / h
- Photoperiod (hrs dark / hrs light): 12 / 12

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
water
Details on oral exposure:
- The test material was administered by gavage to three groups each of ten male and ten female rats, for up to fifty-four consecutive days, at dose levels of 15, 50 and 150 mg/kg/day.
- A control group of ten males and ten females was dosed with vehicle alone (Deoxygenated and demineralised water).
- Two recovery groups, each of five males and five females, were treated with the high dose (150 mg/kg/day) or the vehicle alone for
forty-three consecutive days and then maintained without treatment for a further fourteen days.
Duration of treatment / exposure:
- for up to fifty-five days
Frequency of treatment:
- each day
Doses / concentrations
Remarks:
Doses / Concentrations:
15, 50 and 150 mg/kg/day
Basis:
actual ingested
No. of animals per sex per dose:
10
Control animals:
yes, concurrent vehicle
Positive control:
none

Examinations

Observations and examinations performed and frequency:
- Clinical Observations: All animals were examined for overt signs of toxicity, ill-health and behavioural change immediately before and alter dosing, and one and five hours after dosing, during the working week. Animals were observed immediately before and after dosing, and one hour after dosing at weekends (except for females during parturition where applicable). During the treatment-free period, animals were observed twice daily, morning and afternoon (once daily at weekends). All observations were recorded.
- Functional Observations: Prior to the start of treatment and at weekly intervals thereafter, all non-recovery animals were observed for signs of functional/behavioural toxicity. Functional performance tests were also performed on tive selected males and females per non-recovery dose level, prior to termination, together with an assessment of sensory reactivity to various stimuli.
- BehaviouralAssessments: Detailed individual clinical observations were performed for each animal using a purpose built arena. The following parameters were observed:
Gait Hyper/Hypothermia, Tremors, Skin colour, Twitches, Respiration, Convulsions, Palpebral closure, Bizarre/Abnonnal/Stereotypic behaviour, Urination, Salivation, Defecation, Pilo-erection, Transfer arousal, Exophthalmia, Tail elevation, Lachrymation
- Functional Performance Tests: Purpose·built 44 infra-red beam automated activity monitors were used to assess motor activity. Animals were randomly allocated to the activity monitors. The tests were performed at approximately the same time each day, under similar laboratory conditions.
- Sensory Reactivity: Each animal was individually assessed for sensory reactivity to auditory, visual and proprioceptive stimuli. The following
parameters were observed: Grasp response, Touch escape, Vocalisation, Pupil reflex, Toe pinch, Startle reflex, Tail pinch, Blink reflex, Finger approach
- Bodyweight: Individual bodyweights were recorded on Day l (prior to dosing) and then weekly for males until termination. Females were weighed weekly until mating was evident. Bodyweights were then recorded on Days 0, 7, 14 and 20 post coitum, and on Days 1 and 4 postpartum. Recovery
animals were weighed on Day 1 (prior to dosing) and then weekly until termination.
- Food Consumption: During the maturation period, weekly food consumption was recorded for each cage of adults.This was continued for males after the mating phase. For females showing evidence of mating, food consumption was recorded for the periods covering Days 0-7, 7-14 and 14-20. For females with live litters, food consumption was recorded on Days 1 and 4 post partum.
- Water Consumption: Water intake was observed daily by visual inspection of water bottles for any overt change.
- Laboratory Investigations: Haematological and blood chemical investigations were performed on five males and five females selected from each non-recovery test and control group on Day 14 (day prior to pairing). Blood samples were obtained from the lateral tail vein. Animals were not fasted prior to sampling.
- Urinalytical investigations were performed on five males selected from non-recovery test and
control group during the final week of treatment and on five males selected from each recovery
group during the final week of the fourteen day treatment-free period.
- Haematology: The following parameters were measured on blood collected into tubes containing potassium EDTA anti-coagulant:
Haemoglobin (Hb), Erythrocyte count (RBC), Haematocrit (Het), Erythrocyte indices, Total leucocyte count (WBC), Differential leucocyte count, Platelet count (PLT), Reticulocyte count
- Blood Chemistry: The following parameters were measured on plasma from blood collected into tubes containing lithium heparin anti-coagulant:
Urea Calcium (Ca++), Glucose Inorganic phosphorus (P), Total protein (Tot.Prot.), Aspartate aminotransferase (ASAT), Albumin Alanine aminotransferase (ALAT), Albumin/Globulin (A/G) ratio (by calculation), Alkaline phosphatase (AP), Sodium (Na+), Creatinine (Creat), Potassium (K+), Total cholesterol (Chol), Chloride (Cl-), Total bilirubin (Bili)
- Urinalysis: The following parameters were recorded on collected urine: Volume, Ketones, Specific Gravity, Bilirubin, pH Urobilinogen, Protein, Reducing Substances, Glucose, Blood


Sacrifice and pathology:
GROSS PATHOLOGY: Yes
HISTOPATHOLOGY: Yes
Statistics:
- Haematological, blood chemical, organ weight (absolute and relative to terminal bodyweight),
weekly bodyweight gain, litter weights, offspring bodyweights and quantitative functional
performance data were assessed for dose response relationships by linear regression analysis,
followed by one way analysis of variance (ANOVA) incorporating Levene’s test for homogeneity
of variance.
- Where variances were shown to be homogenous, pairwise comparisons were conducted using Dunnett’s test.
- Where Levene’s test showed unequal variances the data were analysed using non-parametric methods: Kruskal-Wallis ANOVA and Mann-Whitney ‘U’ test.
- The non-parametric methods were also used to analyse implantation loss, offspring sex ratio and
landmark developmental markers.
- The haematology variable basophils was not analysed since consistently greater than 30% of the
data were recorded as the same value.

Results and discussion

Results of examinations

Clinical signs:
effects observed, treatment-related
Mortality:
mortality observed, treatment-related
Body weight and weight changes:
effects observed, treatment-related
Description (incidence and severity):
Females treated with 150 mg/kg/day showed a reduction in group mean bodyweight and bodyweight gain between Day 0 and Day 7 of gestation, although this did not achieve statistical significance [...]. See below.
Food consumption and compound intake (if feeding study):
effects observed, treatment-related
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
no effects observed
Ophthalmological findings:
not examined
Haematological findings:
no effects observed
Clinical biochemistry findings:
no effects observed
Urinalysis findings:
no effects observed
Behaviour (functional findings):
no effects observed
Organ weight findings including organ / body weight ratios:
no effects observed
Gross pathological findings:
no effects observed
Histopathological findings: non-neoplastic:
no effects observed
Histopathological findings: neoplastic:
no effects observed
Details on results:
Mortality.
There were five interim deaths during the study, these were confined to females treated with 150 mg/kg/day. One female (number 76) died during the maturation phase on Day 10. A second female (number 73) was killed in extremis on Day 23 (Day 7 of gestation). Two females were found dead on their Day 22 of gestation (Day 40 of the main study for female 80 and Day 41 of the main study for female 75), The final of the five females (number 72) was killed in extremis on it’s Day 1 of lactation phase (Day 41 of main study).

Clinical signs.
The only toxicological significant observations were detected for the two interim death females that were killed in extremis (numbers 73 and 72), these included incidents of tip-toe gait, hunched posture and pilo erection. One of the females (number 73) also had red/brown staining around the mouth. The deterioration of the females’ condition subsequently led to their termination. No toxicologically significant findings were detected for animals of either sex after the treatment period, or for animals of either sex after the fourteen-day recovery period.

Histopathology.
There were no treatment-related microscopic changes detected for the pituitary or reproductive tissues examined for terminal kill animals after the treatment period. Here were five unscheduled deaths during the course of the study. Three females were found dead and two were killed in extremis, all five females were from the 150 mg/kg/day treatment group. With the possible exception of pyometria reported for female number 72 and focal gastric ulceration for female 73, factors contributing to the death or moribundity in these animals were not evident from histopathological evaluation.

Neurobehaviour.
No treatment-related effects were detected for animals of either sex from all treatment groups after the treatment period. Formal behavioural assessments were not carried out for recovery group animals.

Organ weights.
No treatment-related intergroup differences in organ weights were detected for all treated animals after the treatment period.

Bodyweights.
Females treated with 150 mg/kg/day showed a reduction in group mean bodyweight and bodyweight gain between Day 0 and Day 7 of gestation, although this did not achieve statistical significance it did lead to a statistically significant reduction in bodyweight for these females at Day 1 of lactation.

No effect on bodyweight was detected during maturation for all treated animals; for all treated males and females treated with 50 or 15 mg/kg/day for the remainder of the treatment period and for animals of either sex after the fourteen day treatment free period.

Food Consumption.
Food consumption was reduced for females treated with 150 mg/kg/day during Days 0 to 7 of gestation and Days 1 to 4 of lactation when compared to controls although statistical significance was not achieved.

No treatment related effects in food consumption were detected for any treated males, females treated with 50 or 15 mg/kg/day or animals of either sex after the fourteen day recovery phase.

Water Consumption.
No overt intergroup differences were detected for all animals after the treatment period or for animals after the fourteen day recovery phase.

Haematology.
No treatment-related effects were detected for the haematological parameters investigated prior to mating. Therefore no further haematological analysis was performed.

Blood Chemistry.
No treatment-related intergroup differences in blood chemical parameters were detected prior to mating. Therefore no further blood chemical analysis was performed.

Urinalysis.
No toxicologically significant effects were detected in treated animals when compared to controls, or for animals of either sex after the fourteen day recovery phase.

Reproductive Screening.
Mating.
No adverse effects on mating performance, fertility or gestation lengths were detected.

Offspring Litter Size and Viability.
No intergroup differences were observed for litter size, sex ratio or viability.

Offspring Development.
No treatment-related effects were detected.

Litter Observations.
There were no clinically observable signs of test material toxicity detected in offspring from treated animals.

Effect levels

open allclose all
Dose descriptor:
NOAEL
Effect level:
50 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
female
Basis for effect level:
other: clinical signs; mortality; body weight during lactation
Dose descriptor:
NOAEL
Effect level:
150 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male
Basis for effect level:
other: overall effects

Target system / organ toxicity

Critical effects observed:
not specified

Applicant's summary and conclusion

Conclusions:
The oral administration of GMT 80% to rats by gavage, at dose levels of 150, 50 and 15 mg/kg bw/day, resulted in no treatment related effects for the males treated with 150 mg/kg bw/day but did result in the death of five females treated with 150 mg/kg bw/day. The
NOEL for systemic toxicity was considered to be 150 mg/kg/day for males and 50 mg/kg bw/day for females.