Registration Dossier

Administrative data

Key value for chemical safety assessment

Effects on fertility

Description of key information

- reproduction/developmental screening study according to OECD 422, GLP, RL1, administered doses: 50, 150 and 1000 mg/kg bw/d; NOAEL >= 1000 mg/kg bw/d, read across from Isostearic acid, esters with methyl- α-D-glucose

Link to relevant study records

Referenceopen allclose all

Endpoint:
toxicity to reproduction
Remarks:
other: combined repeated dose and reproduction / developmental screening
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2008-09-25 to 2008-11-14
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Reason / purpose:
reference to same study
Qualifier:
according to
Guideline:
OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)
Version / remarks:
March 1996
Deviations:
no
GLP compliance:
yes
Limit test:
no
Species:
rat
Strain:
other: Wistar Han (Crl:WI(Han))
Sex:
male/female
Details on test animals and environmental conditions:
Accommodation offspring
- Offspring was kept with the dam until termination in Macrolon cages (MIII type, height 18 cm).
Route of administration:
oral: gavage
Vehicle:
other: 1 % aqueous carboxymethyl cellulose (Genfarma, Zaandam, The Netherlands).
Details on exposure:
After acclimatisation, four groups of ten male and ten female Wistar Han rats were exposed by
oral gavage to the test substance at 0, 50, 150, and 1000 mg/kg/day.
Males were exposed for 30 days, i.e. 2 weeks prior to mating, during mating, and up to
termination. Females were exposed for 42 to 44 days, i.e. during 2 weeks prior to mating, during
mating, post-coitum, and during at least 4 days of lactation.
Details on mating procedure:
- M/F ratio per cage: 1/1
- Length of cohabitation: a minimum of 14 days of exposure
- Proof of pregnancy: sperm in vaginal lavage or by appearance of an intravaginal copulatory plug referred to as day 0 post coitum
- After successful mating each pregnant female was caged (how): Females were individually housed in Macrolon cages (MIII type, height 18 cm).
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Quantitative analysis was based on the analytical method validated for the test substance in NOTOX project 488541.
Preparation of formulations was considered acceptable if the mean accuracy was in the range 85% - 115% of the target concentration and if the coefficient of variation was <= 10%. Formulations were considered stable if the relative difference between the stored and freshly taken samples
was <= 10%.
Duration of treatment / exposure:
Offspring: not treated
Males: exposed for 30 days, i.e, 2 weeks prior to mating, during mating, and up to termination
Females: exposed for 42-44 days, i.e, during 2 weeks prior to mating, during mating, during post-coitum, and during at least 4 days of lactation
Frequency of treatment:
Daily treatment
Details on study schedule:
- Parturition F0:
The females were allowed to Iitter normally. Day 1 of lactation was defined as the day when a litter was found completed (i.e. membranes, placentas cleaned up, nest built up and/or feeding of pups started). Females that were littering were left undisturbed.
- Lactation F0:
Examination of maternal care revealed no deficiencies (such as inadequate construction or cleaning of the nest, pups left scattered and cold, physical abuse of pups or apparently inadequate lactation or feeding).
Dose / conc.:
50 mg/kg bw/day (actual dose received)
Remarks:
oral gavage
Dose / conc.:
150 mg/kg bw/day (actual dose received)
Remarks:
oral gavage
Dose / conc.:
1 000 mg/kg bw/day (actual dose received)
Remarks:
oral gavage
No. of animals per sex per dose:
10
Control animals:
yes, concurrent vehicle
Positive control:
no positive control group
Parental animals: Observations and examinations:
At 1000 mg/kg, clinical laboratory investigations revealed statistically significantly reduced haemoglobin, cholesterol and total protein levels (males), and statistically significantly elevated white blood cell counts (females; only for two determined) and alkaline phosphatase levels (males). Increased liver weights (absolute and relative) were noted for high dose males and females. These changes were noted without corroborative findings (e.g. histopathological findings).
No treatment-related changes were noted in any of the remaining parameters investigated in this study (i.e. mortality, clinical appearance, functional observations, body weight, food consumption, macroscopic and microscopic examination, reproduction and breeding).
Oestrous cyclicity (parental animals):
REPRODUCTIVE FUNCTION: ESTROUS CYCLE (PARENTAL ANIMALS)
- Corpora lutea
Sperm parameters (parental animals):
All recorded microscopic findings were within the range of background pathology encountered in Wistar rats of this age in this type of study and occurred at similar incidences and severity in both control and treated rats. The spermatogenic staging profiles were normal for all group 1 and group 4 males evaluated.
Litter observations:
PARAMETERS EXAMINED
The following parameters were examined in offspring:
- Number and sex of pups: on day 1 and 4 of lactation (by assessment of the ano-genital distance)
- Stillbirths, live births, postnatal mortality, if possible defects or cause of death: at day 1 of lactation and daily thereafter
- Clinical signs (detailed clinical observations, including abnormal behaviour): at least once daily
- Body weights: live pups were weighed during lactation on Days 1 and 4.

PATHOLOGY OFFSPRING
- Pups were killed by decapitation on Day 5 01 lactation or shortly thereafter.
- The stomach was examined For the presence of milk.
- Descriptions of all external abnormalities were recorded. If possible, detects or cause of death were evaluated. Any abnormal pup, organ or tissue was preserved in 10% buffered formalin, for possible further examination.
Postmortem examinations (parental animals):
There were no unscheduled deaths.
Macroscopic Findings

Macroscopic examinations were performed of the cranial, thoracic and abdominal tissues and organs, with special attention being paid to the reproductive organs. All macroscopic findings were considered to be spontaneous in nature and did not distinguish treated animals from the controls.

Microscopic Findings
All recorded microscopic findings were within the range of background pathology encountered in Wistar rats of this age in this type of study and occurred at similar incidences and severity in both control and treated rats.
Postmortem examinations (offspring):
Pups were killed by decapitation on Day 5 of lactation or shortly thereafter.

All offspring was sexed and externally examined. The stomach was examined for the presence of milk. Descriptions of all external abnormalities were recorded. If possible, defects or cause of death were evaluated. Any abnormal pup, organ or tissue was preserved in 10% buffered formalin, for possible further examination.
No treatment-related changes were noted for reproduction, breeding and pup development.
Reproductive indices:
Breeding parameters were unaffected by treatment up to 1000 mg/kg body weight/day.
Postnatal loss and viability index were similar for the control and treated groups.
Offspring viability indices:
Breeding parameters were unaffected by treatment up to 1000 mg/kg body weightlday.
Postnatal loss and viability index were similar for the control and treated groups.
Clinical signs:
no effects observed
Dermal irritation (if dermal study):
not examined
Mortality:
no mortality observed
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
no effects observed
Food efficiency:
no effects observed
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not examined
Haematological findings:
effects observed, treatment-related
Description (incidence and severity):
At 1000 mg/kg, haemoglobin levels were slightly reduced for males (statistical significant at 5%) and white blood cell counts (WBC) were higher for females (statistical significant at 1%; only determined for two females). A statistical significant reduction in prothrombin time (PT) was noted for males at 150 mg/kg, but in the absence of a dose-dependent trend it was considered to be of no toxicological relevance.
Clinical biochemistry findings:
effects observed, treatment-related
Description (incidence and severity):
At 1000 mg/kg, males showed elevated alkaline phosphatase (ALP) levels (statistical significant at 1%), and significantly reduced levels of cholesterol and total protein compared to vehicle controls (both statistical significant at 5%).
Aspartate aminotransferase (ASAT) levels showed a reduction for females at all treatment levels without a dose response relationship. However, for this parameter, the values for the concurrent control animals were much higher than data from historical controls (historical control mean = 66.6, Group 1 mean = 121.4), and as such, the reduced ASAT levels were not considered to be toxicologically relevant. The cause of these increased values for the concurrent control group was unclear. However, as no corroborative findings were noted it was not considered toxicological relevant.
Chloride levels were slightly lower for females at 150 and 1000 mg/kg. However, as this change was very slight and within the normal range, it was not considered toxicologically relevant. All other statistically significant changes from controls (decreased glucose levels at 50 mg/kg and increased inorganic phosphate values at 150 mg/kg, both for males) were considered to be of no toxicological significance as they occurred in the absence of a treatment-related distribution.
Urinalysis findings:
not examined
Behaviour (functional findings):
no effects observed
Description (incidence and severity):
Hearing ability, pupillary reflex, static righting reflex, grip strength and motor activity were normal in the selected animals.
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Histopathological findings: non-neoplastic:
no effects observed
Description (incidence and severity):
All recorded microscopic findings were within the range of background pathology encountered in Wistar Han rats of this age in this type of study and occurred at similar incidences and severity in both control and treated rats.
The spermatogenic staging profiles were normal for all Group 1 and Group 4 males evaluated.
Histopathological findings: neoplastic:
not examined
Other effects:
no effects observed
Reproductive function: oestrous cycle:
no effects observed
Description (incidence and severity):
Reproduction parameters were unaffected by treatment up to 1000 mg/kg body weight/day.
Reproductive function: sperm measures:
no effects observed
Description (incidence and severity):
Reproduction parameters were unaffected by treatment up to 1000 mg/kg body weight/day.
Reproductive performance:
no effects observed
Description (incidence and severity):
Reproduction parameters were unaffected by treatment up to 1000 mg/kg body weight/day.
REPRODUCTIVE FUNCTION: ESTROUS CYCLE (PARENTAL ANIMALS)
- Corpora lutea

REPRODUCTIVE FUNCTION: SPERM MEASURES (PARENTAL ANIMALS)
- Staging of Spermatogenesis

For further details please find under chapter: 7.5.1 "Repeated dose toxicity: oral".
Key result
Dose descriptor:
NOAEL
Effect level:
>= 1 000 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: see 'Remark'
Key result
Dose descriptor:
NOEL
Effect level:
150 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: see 'Remark'
Key result
Dose descriptor:
NOAEL
Effect level:
>= 1 000 mg/kg bw/day (nominal)
Sex:
male/female
Basis for effect level:
other: - No treatment-related changes on reproduction, breeding and pup development).
Remarks on result:
other: Generation: reproduction, breeding, development
Clinical signs:
no effects observed
Description (incidence and severity):
small size, bluish colour, blue spot on the neck and eye, scabbing of the right cheek, pale appearance and insufficient milk in the stomach. No relationship with treatment was established for these observations and they were considered to be of no toxicoiogical significance.
Dermal irritation (if dermal study):
not examined
Mortality / viability:
no mortality observed
Body weight and weight changes:
no effects observed
Description (incidence and severity):
Pup (mean) body weights were in the same range for the control and treated groups.
Food consumption and compound intake (if feeding study):
not examined
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not examined
Haematological findings:
not examined
Clinical biochemistry findings:
no effects observed
Urinalysis findings:
not examined
Sexual maturation:
not examined
Organ weight findings including organ / body weight ratios:
not examined
Gross pathological findings:
no effects observed
Description (incidence and severity):
Findings consisted of autolysis of pups found dead at the first Iitter check, scabbing of the right cheek, and insufficient milk in the stomach. No relationship with treatment was established for these observations and they were considered to be of no toxicoiogical significance.
Histopathological findings:
not examined
Other effects:
no effects observed
Behaviour (functional findings):
not examined
Developmental immunotoxicity:
not examined
VIABILITY (OFFSPRING)
- Viability index (=Number of alive pups before planned necropsy/Number of pups born alive): 0 mg/kg bw: : 100% , 50 mg/kg bw: : 100%, 150 mg/kg bw: : 99.2%, 1000 mg/kg bw: : 98.4% (significant at 5 %)
- Dead pups at first litter check: 0 mg/kg bw: 3 males, 2 females; 50 mg/kg bw: 1 male, 1 female, 150 mg/kg bw: 0; 1000 mg/kg bw: 1 female
- Dead pups post natal: at 0, 50 mg/kg bw: 0, at 150 mg/kg bw: 1 male, at 1000 mg/kg bw: 1 male, 1 female from one litter
- 10 litters/dose group

CLINICAL SIGNS (OFFSPRING)
- small size, bluish colour, blue spot on the neck and eye, scabbing of the right cheek, pale appearance and insufficient milk in the stomach. No relationship with treatment was established for these observations and they were considered to be of no toxicoiogical significance.

BODY WEIGHT (OFFSPRING)
Pup (mean) body weights were in the same range for the control and treated groups.

GROSS PATHOLOGY (OFFSPRING)
- Findings consisted of autolysis of pups found dead at the first Iitter check, scabbing of the right cheek, and insufficient milk in the stomach. No relationship with treatment was established for these observations and they were considered to be of no toxicoiogical significance.


Key result
Dose descriptor:
NOAEL
Generation:
F1
Effect level:
1 000 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Remarks on result:
other: No adverse effects were observed
Reproductive effects observed:
not specified
Conclusions:
In conclusion, treatment with Isostearic acid, esters with methyl α-D-glucoside by oral gavage in male and female Wistar Han rats at dose levels of 50, 150 and 1000 mg/kg body weight/day revealed parental toxicity at 1000 mg/kg bw/day. No reproduction, breeding and developmental toxicity was observed for treatment up to 1000 mg/kg bw/day.
Executive summary:

In a Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test according OECD 422 test substance Isostearic acid, esters with methyl α-D-glucoside in 1 % aqueous carboxymethyl cellulose was administered to 10 male and 10 female Wistar Han rats/dose group by daily oral gavage at dose levels of 0, 50, 150, and 1000 mg/kg bw/day. The males were exposed for 2 weeks prior to mating, during mating, and up to termination (for 30 days). The females were exposed for 2 weeks prior to mating, during mating, during post-coitum, and at least 4 days of lactation (for 42 to 44 days). 10 litters per dose group were delivered.

At 1000 mg/kg bw/day statistically significantly reduced haemoglobin, cholesterol and total protein levels (males), and elevated white blood cell counts (determined for only two females) plus alkaline phosphatase levels (males) were found. Increased liver weights (absolute and relative) were noted for high dose males and females.

No treatment-related changes were noted in any of the remaining parameters investigated in this study (i.e. reproduction, breeding, pup development, and of the adults: mortality, clinical appearance, functional observations, body weight, food consumption, macroscopic and microscopic examination,).

The parental NOEL is 150 mg/kg bw/day, based on the findings noted at 1000 mg/kg bw/day

The parental NOAEL is >= 1000 mg/kg bw/day, based on the findings noted at 1000 mg/kg bw/day which were not considered adverse and were without any corroborative findings like histopathological changes.

The reproduction, breeding and developmental NOAEL is >= 1000 mg/kg bw/d.

This Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test in the rat is acceptable and satisfies the guideline requirements of OECD TG 422.

Endpoint:
screening for reproductive / developmental toxicity
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
1. HYPOTHESIS FOR THE ANALOGUE APPROACH
This read-across is based on the hypothesis that source substance is constituted of the target substance (alpha methyl glucoside) esterified to Isostearic acid and therefore exhibit partially similar toxicological behaviour due to similarity in their structure. During synthesis of Isostearic acid esters with methyl-α-D-glucose the four OH-groups of the methyl glucose are partially esterified with isostearate groups. The molar ratio of methyl glucose and isostearic acid is chosen close to 1:2 which means that the products may be a mixture of non reacted methyl glucose and its 4 monostearates, 6 distearates, 4 tristearates and 1 tetrastearate isomers. These numbers will increase accordingly, if the cyclic form of glucose is in equilibrium with its linear form and the other anomer (hemiacetalic carbon). A possible hydrolysis results in alpha methyl glucoside and excess Isostearic acid.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
The target substance alpha methyl glucoside is a monoconstituent substance composed of a methyl-group which is o-glycosidic bound to the α-D-glucose core structure.

The source substance Isostearic acid esters with Methyl-α-D-glucose is an UVCB with a composition of 80% alpha methyl glucoside isostearate esters (mainly di-), 16% isostearic acid and 4% alpha methyl glucoside.

3. ANALOGUE APPROACH JUSTIFICATION
For more detailed information please refer to the attached justification for read-across.

4. DATA MATRIX
For more detailed information please refer to the attached justification for read-across.
Reason / purpose:
read-across source
Clinical signs:
no effects observed
Dermal irritation (if dermal study):
not examined
Mortality:
no mortality observed
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
no effects observed
Food efficiency:
no effects observed
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not examined
Haematological findings:
effects observed, treatment-related
Description (incidence and severity):
At 1000 mg/kg, haemoglobin levels were slightly reduced for males (statistical significant at 5%) and white blood cell counts (WBC) were higher for females (statistical significant at 1%; only determined for two females). A statistical significant reduction in prothrombin time (PT) was noted for males at 150 mg/kg, but in the absence of a dose-dependent trend it was considered to be of no toxicological relevance.
Clinical biochemistry findings:
effects observed, treatment-related
Description (incidence and severity):
At 1000 mg/kg, males showed elevated alkaline phosphatase (ALP) levels (statistical significant at 1%), and significantly reduced levels of cholesterol and total protein compared to vehicle controls (both statistical significant at 5%).
Aspartate aminotransferase (ASAT) levels showed a reduction for females at all treatment levels without a dose response relationship. However, for this parameter, the values for the concurrent control animals were much higher than data from historical controls (historical control mean = 66.6, Group 1 mean = 121.4), and as such, the reduced ASAT levels were not considered to be toxicologically relevant. The cause of these increased values for the concurrent control group was unclear. However, as no corroborative findings were noted it was not considered toxicological relevant.
Chloride levels were slightly lower for females at 150 and 1000 mg/kg. However, as this change was very slight and within the normal range, it was not considered toxicologically relevant. All other statistically significant changes from controls (decreased glucose levels at 50 mg/kg and increased inorganic phosphate values at 150 mg/kg, both for males) were considered to be of no toxicological significance as they occurred in the absence of a treatment-related distribution.
Urinalysis findings:
not examined
Behaviour (functional findings):
no effects observed
Description (incidence and severity):
Hearing ability, pupillary reflex, static righting reflex, grip strength and motor activity were normal in the selected animals.
Immunological findings:
not examined
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Histopathological findings: non-neoplastic:
no effects observed
Description (incidence and severity):
All recorded microscopic findings were within the range of background pathology encountered in Wistar Han rats of this age in this type of study and occurred at similar incidences and severity in both control and treated rats.
The spermatogenic staging profiles were normal for all Group 1 and Group 4 males evaluated.
Histopathological findings: neoplastic:
not examined
Other effects:
no effects observed
Reproductive function: oestrous cycle:
no effects observed
Description (incidence and severity):
Reproduction parameters were unaffected by treatment up to 1000 mg/kg body weight/day.
Reproductive function: sperm measures:
no effects observed
Description (incidence and severity):
Reproduction parameters were unaffected by treatment up to 1000 mg/kg body weight/day.
Reproductive performance:
no effects observed
Description (incidence and severity):
Reproduction parameters were unaffected by treatment up to 1000 mg/kg body weight/day.
REPRODUCTIVE FUNCTION: ESTROUS CYCLE (PARENTAL ANIMALS)
- Corpora lutea

REPRODUCTIVE FUNCTION: SPERM MEASURES (PARENTAL ANIMALS)
- Staging of Spermatogenesis

For further details please find under chapter: 7.5.1 "Repeated dose toxicity: oral".
Key result
Dose descriptor:
NOAEL
Effect level:
>= 1 000 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: see remarks
Key result
Dose descriptor:
NOEL
Effect level:
150 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: see reamarks
Key result
Dose descriptor:
NOAEL
Effect level:
>= 1 000 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: see remarks
Clinical signs:
no effects observed
Description (incidence and severity):
small size, bluish colour, blue spot on the neck and eye, scabbing of the right cheek, pale appearance and insufficient milk in the stomach. No relationship with treatment was established for these observations and they were considered to be of no toxicoiogical significance.
Dermal irritation (if dermal study):
not examined
Mortality / viability:
no mortality observed
Body weight and weight changes:
no effects observed
Description (incidence and severity):
Pup (mean) body weights were in the same range for the control and treated groups.
Food consumption and compound intake (if feeding study):
not examined
Food efficiency:
not examined
Water consumption and compound intake (if drinking water study):
not examined
Ophthalmological findings:
not examined
Haematological findings:
not examined
Clinical biochemistry findings:
no effects observed
Urinalysis findings:
not examined
Sexual maturation:
not examined
Organ weight findings including organ / body weight ratios:
not examined
Gross pathological findings:
no effects observed
Description (incidence and severity):
Findings consisted of autolysis of pups found dead at the first Iitter check, scabbing of the right cheek, and insufficient milk in the stomach. No relationship with treatment was established for these observations and they were considered to be of no toxicoiogical significance.
Histopathological findings:
not examined
Other effects:
no effects observed
Behaviour (functional findings):
not examined
Developmental immunotoxicity:
not examined
VIABILITY (OFFSPRING)
- Viability index (=Number of alive pups before planned necropsy/Number of pups born alive): 0 mg/kg bw: : 100% , 50 mg/kg bw: : 100%, 150 mg/kg bw: : 99.2%, 1000 mg/kg bw: : 98.4% (significant at 5 %)
- Dead pups at first litter check: 0 mg/kg bw: 3 males, 2 females; 50 mg/kg bw: 1 male, 1 female, 150 mg/kg bw: 0; 1000 mg/kg bw: 1 female
- Dead pups post natal: at 0, 50 mg/kg bw: 0, at 150 mg/kg bw: 1 male, at 1000 mg/kg bw: 1 male, 1 female from one litter
- 10 litters/dose group

CLINICAL SIGNS (OFFSPRING)
- small size, bluish colour, blue spot on the neck and eye, scabbing of the right cheek, pale appearance and insufficient milk in the stomach. No relationship with treatment was established for these observations and they were considered to be of no toxicoiogical significance.

BODY WEIGHT (OFFSPRING)
Pup (mean) body weights were in the same range for the control and treated groups.

GROSS PATHOLOGY (OFFSPRING)
- Findings consisted of autolysis of pups found dead at the first Iitter check, scabbing of the right cheek, and insufficient milk in the stomach. No relationship with treatment was established for these observations and they were considered to be of no toxicoiogical significance.


Key result
Dose descriptor:
NOAEL
Generation:
F1
Effect level:
1 000 mg/kg bw/day (nominal)
Based on:
test mat.
Sex:
male/female
Remarks on result:
other: No adverse effects were observed
Key result
Reproductive effects observed:
not specified
Conclusions:
In conclusion, treatment with Isostearic acid, esters with methyl α-D-glucoside by oral gavage in male and female Wistar Han rats at dose levels of 50, 150 and 1000 mg/kg body weight/day revealed parental toxicity at 1000 mg/kg bw/day. No reproduction, breeding and developmental toxicity was observed for treatment up to 1000 mg/kg bw/day.
Executive summary:

In a Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test according OECD 422test substanceIsostearic acid, esterswith methyl α-D-glucosidein 1 % aqueous carboxymethyl cellulose was administered to 10 male and 10 female Wistar Han rats/dose groupby daily oral gavageat dose levels of 0, 50, 150, and 1000 mg/kg bw/day.The males were exposed for 2 weeks prior to mating, during mating, and up to termination (for 30 days). The females were exposed for 2 weeks prior to mating, during mating, during post-coitum, and at least 4 days of lactation (for 42 to 44 days). 10 litters per dose group were delivered.

At 1000mg/kg bw/daystatistically significantly reduced haemoglobin, cholesterol and total protein levels (males), and elevated white blood cell counts (determined for only two females) plus alkaline phosphatase levels (males) were found. Increased liver weights (absolute and relative) were noted for high dose males and females.

No treatment-related changes were noted in any of the remaining parameters investigated in this study (i.e. reproduction, breeding, pup development, and of the adults: mortality, clinical appearance, functional observations, body weight, food consumption, macroscopic and microscopic examination).

The parental NOEL is150mg/kgbw/day, based on the findings noted at 1000 mg/kg bw/day

The parental NOAEL is >=1000mg/kgbw/day,based on the findings noted at 1000 mg/kg bw/day which were not considered adverse and were without any corroborative findings like histopathological changes.

The reproduction, breeding and developmental NOAEL is >= 1000mg/kgbw/d.

This Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test in the rat isacceptableand satisfies the guideline requirements of OECD TG 422.

Effect on fertility: via oral route
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEL
1 000 mg/kg bw/day
Study duration:
subacute
Species:
rat
Quality of whole database:
The study was conducted according to OECD guideline 422 and GLP, thus, it is considered to be of high quality. Based on the different molecular weights of source and target substance the NOAEL value was adjusted.
Effect on fertility: via inhalation route
Endpoint conclusion:
no study available
Effect on fertility: via dermal route
Endpoint conclusion:
no study available
Additional information

No experimental data on reproduction/developmental toxicity are available for the target substance alpha methyl glucoside. However, reliable data from a reproduction/developmental screening study conducted with the closely related source substance Isostearic acid, esters with methylα-D-glucoside is available. A justification for read-across is given below.

 

Combined 28-day repeated dose toxicity study with a reproduction/developmental toxicity screening test:

In a Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test according OECD 422 test substance Isostearic acid, esters with methylα-D-glucoside in 1 % aqueous carboxymethyl cellulose was administered to 10 male and 10 female Wistar Han rats/dose group by daily oral gavage at dose levels of 0, 50, 150, and 1000 mg/kg bw/day. The males were exposed for 2 weeks prior to mating, during mating, and up to termination (for 30 days). The females were exposed for 2 weeks prior to mating, during mating, during post-coitum, and at least 4 days of lactation (for 42 to 44 days). 10 litters per dose group were delivered.

At 1000 mg/kg bw/day statistically significantly reduced haemoglobin, cholesterol and total protein levels (males), and elevated white blood cell counts (determined for only two females) plus alkaline phosphatase levels (males) were found. Increased liver weights (absolute and relative) were noted for high dose males and females.

No treatment-related changes were noted in any of the remaining parameters investigated in this study (i.e. reproduction, breeding, pup development, and of the adults: mortality, clinical appearance, functional observations, body weight, food consumption, macroscopic and microscopic examination,).

The parental NOEL is 150 mg/kg bw/day, based on the findings noted at 1000 mg/kg bw/day

The parental NOAEL is >= 1000 mg/kg bw/day, based on the findings noted at 1000 mg/kg bw/day which were not considered adverse and were without any corroborative findings like histopathological changes.

The reproduction, breeding and developmental

NOAEL is >= 1000 mg/kg bw/d.

 

This Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test in the rat is acceptable and satisfies the guideline requirements of OECD TG 422.

Based on the available information, the reproduction/developmental toxicity of alpha methyl glucoside is considered to be low. There are no data gaps for reproduction/developmental toxicity. Even though there is no information on reproduction/developmental toxicity in humans, there is no reason to believe that the results observed in experimental animals would not be relevant for human health.

 

Justification for read-across

For details on substance identity, toxicokinetics and detailed toxicological profiles, please refer also to the general justification for read-across attached as pdf document to section 13 of the IUCLID file.

 

Analogue approach justification

The read-across hypothesis is based on similar break down products of target and source substance, i.e. the target substance (alpha methyl glucoside) is one of two break down products of the source substance (Isostearic acid, esters with Methyl-α-D-glucose). According to scenario 1 of the Read-across Assessment Framework (RAAF) this analogue approach is based on the (bio) transformation of the source substance to common compounds, i.e. the target substance alpha methyl glucoside and Isostearic acid. Based on the available experimental data, including genotoxicity studies, the read-across strategy is supported by a similar toxicological behaviour of the two substances and their break-down products, respectively. Although there is a difference in absorption, for both substances a very low acute toxicity and mutagenicity was shown. However, in accordance with ECHA guidance on information requirements chapter R 7.c absorption of Isostearic acid, esters with methyl-α-D-glucose in the GI-tract is considered unlikely due to its size. The main metabolism pathway of the unchanged source substance would then be biotransformation by xenobiotic metabolism, i.e. functionalisation, conjugation and subsequent biliary excretion. However, unspecific hydrolysis of the source substance (Isostearic acid, esters with methyl-α-D-glucose) during GI-tract passage is more likely to occur resulting in its breakdown products, namely alpha methyl glucoside and Isostearic acid.

Alpha methyl glucoside (target substance) is a non-metabolisable glucose analogue which is used in several published studies to investigate cellular glucose uptake (Segal et al., 1973; Lee et al., 2007; Prieto et al., 1996; Genel et al., 1970). Alpha methyl glucoside enters the cell via the ubiquitously occurring SGLT transporter. Recovery of nearly 100% of labelled alpha methyl glucoside revealed a full absorption in various tissues. Due to reabsorption by the kidney, its concentration is elevated in the renal brush border membrane (Lee et al., 2007). This increase of alpha methyl glucoside is only limited by the ion gradient resulting from sodium symport. Alpha methyl-glucoside is considered to be mainly renally excreted. The other remaining break down product Isotearic acid is metabolised via β-oxidation and is thereby eliminated by the intermediary metabolism and thus, indistinguishable from fatty acids from other sources including diet.

 

Structural similarity

a. Structural similarity and functional groups

The target substance, alpha methyl glucoside, consists of alpha-D-glucose which forms an o-glycosidic bond with a methyl-group at C1. Since several studies confirm that alpha methyl glucoside should be regarded to as a non-metabolizable sugar in mammalian cells, it can be concluded that the substance is renally excreted without transformation (Segal et al., 1973; Lee et al., 2007; Prieto et al., 1996; Genel et al., 1970). Although not metabolisable by mammalian cells it was shown that alpha methyl glucoside is metabolised by several bacteria except these ones occurring most frequently in the GI flora (Devriese et al., 1996, Tittsler & Sandholzer, 1935, Koser & Saunders, 1932).

The source substance, Isostearic acid esters with methyl-α-D-glucose, consists of one to four C18 aliphatic chains which are esterified to alpha methyl glucoside. Although this substance has a very lipophilic character (logKow > 6.5, water solubility < 5E-004 g/L and a high molecular weight (weighted mean) 690.31 g/mol) it cannot be excluded that it is absorbed to little extent. Subsequent to uptake unhydrolysed Isostearic acid, esters with methyl-α-D-glucose will to some extent undergo biotransformation by xenobiotic metabolism and subsequently biliary excreted, on the other hand unspecific hydrolysis is likely to occur and two fragments will emerge of which one is readily metabolised by fatty acid metabolism, i.e. β-oxidation of the aliphatic chain and the other one, alpha methyl glucoside (= target substance), is excreted unchanged. However, since Isostearic acid, esters with methyl-α-D-glucose is an UVCB consisting of an estimated amount of 4% of methyl-α-D-glucose, it must be assumed that studies conducted with the source substance are also performed with 4% of the target substance.

However, there are some differences between the target substance and the source substance regarding their physicochemical properties and consequently their toxicological effects.

b. Common breakdown products:

The metabolism expected to occur in the unhydrolysed source substance Isostearic acid, esters with methyl-α-D-glucose due to its size is functionalisation, conjugation and excretion. On the other hand hydrolysis of the isostearic acid moeity is likely to occur. The rate of hydrolysis is assumed to be enzyme-mediated and may thus be limited. Further degradation may be the metabolism of the fatty acid chain via β-oxidation. However, since the source substance is considered to be highly lipophilic, intestinal absorption may be limited for the unhydrolysed substance. However, the source substance is considered to be unspecifically hydrolysed in the GI-tract and subsequently absorbed and further metabolised. In case of alpha methyl glucoside (one of two breakdown products), a known non-metabolisable molecule, distribution preferentially to the kidney and in tissues exhibiting the SGLT1 and SGLT2 transporter occurs. This uptake and transient increase of concentration is also driven by renal reabsorption and slow excretion but this increase is limited by sodium symport. Finally, alpha methyl glucoside is considered to be renally excreted.

c. Differences

As described above alpha methyl glucoside and Isostearic acid, esters with methyl-α-D-glucose are distinguished by the presence or absence of the C18 alkyl-chains.Associated with the presence of these alkyl chains also differences in the physicochemical properties of both substances occur, i.e. differences in water solubility, partition coefficient, molecular weight etc. These physicochemical characteristics are also decisive for absorption of the source substance either oral (via GI-tract), dermal or by inhalation. Exposure to the source substance via inhalation route can be excluded due to its waxy appearance and its low vapour pressure. Due to its high molecular weight and log Kow the absorption of the unhydrolysed source substance is also limited via the dermal and the oral route. However, as explained above the composition of the source substance substantiates an exposure to the target substance as well. In contrast, dermal absorption of alpha methyl glucoside is likely due to its small molecular weight. Respiratory absorption of alpha methyl glucoside cannot be fully excluded due to its granular form although its median particle size is 100 µm, thus, it is considered that the substance is not inhalable according to ECHA guidance on information requirements Chapter R.7.c.

Since alpha methyl glucoside is produced and handled only as an intermediate consumer exposure is assumed to be marginal, thus, exposure via the oral route is not expected.

Dermal absorption of alpha methyl glucoside is also considered to be low due to its low log Kow (-2.5) it is presumably to hydrophilic to cross the stratum corneum.

 

Comparison of reproduction/developmental data

Endpoint

Target substance

Source substance

 

Alpha methyl glucoside

 

Isostearic acid, esters with methyl-α-D-glucoside

 

Reproduction/

developmental screening

 

No data, read-across

 

OECD 422, female/male Wistar rats, RL 1, GLP, dosages: 50, 150, 1000 mg/kg bw/day, exposure: 30d (males), 44d (females)

 

 - at 100 mg/kg bw significant alterations in haematology, clinical biochemistry and organ weights were observed, the effects are not considered to be adverse,

 - NOAEL > 1000 mg/kg bw/d, 

 - NOEL > 150 mg/kg bw/d and

 - reproduction, breeding and developmental - NOAEL ≥1000 mg/kg bw/d

 

 

Reproduction/developmental toxicity - no classification according to Regulation (EC) No 1272/2008 (CLP) and the Globally Harmonized System for Classification and Labelling of Chemicals (GHS).

No experimental data are available for the target substance.

The closely related source substance Isostearic acid, esters with methyl-α-D-glucoside revealed a NOAEL > 1000 mg/kg bw/d for female/male rats.

Quality of the experimental data of the analogues:

The source substance Isostearic acid, esters with methyl-α-D-glucoside has been tested in a reliable study according to OECD TG 422. The tests have been conducted according to GLP criteria. Therefore these data have no uncertainties and can be used in an analogue approach. The available data from the source chemical is sufficiently reliable to justify the read-across approach.

 

Conclusion for read-across

The structural similarities between the breakdown products of the source substance and the target substance as presented above support the read-across hypothesis. Adequate and reliable scientific information indicates that the source substance and its degradation products and target substance have similar toxicity profiles under the experimental conditions in the considered studies for the endpoint reproduction/developmental screening. Thus, the results obtained with the source substance Isostearic acid, esters with methyl-alpha-D-glucoside are considered to be also relevant for the target substance alpha methyl glucoside.

 

 

References:

Lee, Y. J., & Han, H. J. (2007). Regulatory mechanisms of Na+/glucose cotransporters in renal proximal tubule cells.Kidney International,72, S27-S35.

Segal, S., Genel, M., Holtzapple, P., & Rea, C. (1973). Transport of alpha-methyl-D-glucoside by human kidney cortex.Metabolism,22(1), 67-76.

Prieto, R. M., Ferrer, M., & Tur, J. A. (1996). Changes in intestinal alpha-methyl-D-glucoside uptake due to pregnancy and lactation in rats.Digestion,57(1), 16-21.

Genel, M., London, D., Holtzapple, P. G., & Segal, S. (1971). Uptake of alpha-methylglucoside by normal and diabetic human jejunal mucosa.Translational Research,77(5), 743-750.

Enoch, S. J., Madden, J. C., & Cronin, M. T. D. (2008). Identification of mechanisms of toxic action for skin sensitisation using a SMARTS pattern based approach.SAR and QSAR in Environmental Research,19(5-6), 555-578.

Koser, S. A., & Saunders, F. (1932). The Fermentation of Alpha-Methyl-D-Glucoside by Members of the Coli-areogenes Group.Journal of bacteriology,24(4), 267.

Tittsler, R. P., & Sandholzer, L. A. (1935). The fermentation of alpha-methylglucoside by bacteria.Journal of bacteriology,29(4), 363.

Devriese, L. A., Pot, B., & Collins, M. D. (1993). Phenotypic identification of the genus Enterococcus and differentiation of phylogenetically distinct enterococcal species and species groups.Journal of Applied Microbiology,75(5), 399-408.

 

 

 

Effects on developmental toxicity

Description of key information

- reproduction/developmental screening study according to OECD 422, GLP, RL1, administered doses: 50, 150 and 1000 mg/kg bw/d; NOAEL >= 1000 mg/kg bw/d, read across from Isostearic acid, esters with methyl-α-glucose

Effect on developmental toxicity: via oral route
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEL
1 000 mg/kg bw/day
Study duration:
subacute
Species:
rat
Quality of whole database:
The study was conducted according to OECD guideline 422 and GLP, thus, it is considered to be of high quality. Based on the different molecular weight of the source and the target substance the NOAEL value was adjusted.
Effect on developmental toxicity: via inhalation route
Endpoint conclusion:
no study available
Effect on developmental toxicity: via dermal route
Endpoint conclusion:
no study available

Justification for classification or non-classification

Based on the available, reliable and relevant data alpha methyl glucoside does not need to be classified according to Regulation (EC) No 1272/2008 (CLP) and the Globally Harmonized System for Classification and Labelling of Chemicals (GHS) with respect to reproduction/developmental toxicity.