Methanesulphonic acid

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Link to relevant study records

Reference

Endpoint:

screening for reproductive / developmental toxicity

Remarks:

based on test type (migrated information)

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study with GLP

Qualifier:

according to guideline

Guideline:

OECD Guideline 421 (Reproduction / Developmental Toxicity Screening Test)

GLP compliance:

yes

Remarks:

CIT Research Laboratories, France

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories France, L’Arbresle, France
- Age at study initiation: (P) 10 weeks
- Weight at study initiation: (P) Males: 408 g (350-441); Females: 241 g (211-267)
- Housing: single
- Diet (e.g. ad libitum): A04 C pelleted maintenance diet
- Water (e.g. ad libitum): bottles containing tap water
- Acclimation period: 11 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22±2
- Humidity (%): 50±20
- Air changes (per hr): 12 cycles
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: gavage

Vehicle:

water

Details on exposure:

PREPARATION OF DOSING SOLUTIONS: The test item was administered as a solution in the vehicle in order to achieve concentrations of 25, 50 and 100 mg/mL, expressed as active substance. The dosage forms were adjusted to a pH of 7.0 with NaOH.


VEHICLE
- Concentration in vehicle: 25, 50 and 100 mg/mL
- Amount of vehicle (if gavage): 10 ml/kg bw

Details on mating procedure:

- M/F ratio per cage: 1:1
- Length of cohabitation: overnight
- Proof of pregnancy: sperm in vaginal smear referred to as day 0 of pregnancy
- Further matings after two unsuccessful attempts: yes (Each female was placed with the same male until mating occurred or 14 days had elapsed and the pre-coital time was calculated)

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Throughout the study, a satisfactory agreement was observed between the nominal and actual concentrations of the test item in the administered dosage forms, since the deviations from nominal concentration were in an acceptable range of ± 10%.

Duration of treatment / exposure:

males: 42 days (28 days pre-mating and 14 days mating period)
females: at least 54 days (28 days pre-mating, 1-14 days mating, 21-22 days pregnancy, 4 days lactation and 5 days post-natal period)

Frequency of treatment:

daily

Details on study schedule:

- Age at mating of the mated animals in the study: ca. 15-16 weeks

Remarks:

Doses / Concentrations:
250, 500 and 1000 mg/kg bw
Basis:
actual ingested

No. of animals per sex per dose:

12

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: The dose-levels were selected on the basis of a 2-week toxicity study where no relevant signs of toxicity were observed at dose rates of 333, 666 or 1000 mg/kg bw/day.

Parental animals: Observations and examinations:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Each animal was checked at least twice a day for mortality and signs of morbidity during the treatment period. Animals found dead were subjected to a macroscopic post-mortem examination. Each animal was observed at least once a day, at approximately the same time for the recording of clinical signs.


BODY WEIGHT: Yes
- Time schedule for examinations: The body weight of each male was recorded on the first day of treatment (day 1), then once a week until sacrifice. The body weight of each female was recorded on the first day of treatment (day 1), then once a week until mated, then on days 0, 7, 14 and 20 post-coitum and on days 1 and 4 post-partum.


FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each animal determined: The quantity of food consumed by each male was recorded once a week from the first day of treatment (except during the mating period) until sacrifice. The quantity of food consumed by each female was recorded once a week during the pre-mating period and then on the following intervals: days 0-7, 7-14, 14-20 post-coitum, and days 1-4 post-partum. No food consumption was recorded for the females during the mating period.

Litter observations:

PARAMETERS EXAMINED
The following parameters were examined in F1 offspring: number and sex of pups, stillbirths, live births, postnatal mortality, presence of gross anomalies, weight gain, physical or behavioural abnormalities


GROSS EXAMINATION OF DEAD PUPS: yes, for external and internal abnormalities; possible cause of death was determined for pups born or found dead.

Postmortem examinations (parental animals):

SACRIFICE
- Male animals: All surviving animals [after the end of the mating period]
- Maternal animals: All surviving animals [on day 5 post-partum, females which had not delivered on day 25 post-coitum were sacrificed after day 25 post-coitum, and females which did not mate were sacrificed at least 1 week after the end of the mating period]. In all females, the number of implantation sites and corpora lutea were recorded. In addition, in the females which did not mate or did not deliver, the implantation sites were classified, whenever appropriate, as scars, early resorptions, late resorptions, live fetuses or dead fetuses. Furthermore, in the females which did not mate or were apparently non-pregnant, the presence of implantation scars on the uterus was checked using the ammonium sulphide staining technique.


GROSS NECROPSY
- Gross necropsy consisted of external and internal examinations including the cervical, thoracic, and abdominal viscera with special attention paid to the reproductive organs.


HISTOPATHOLOGY / ORGAN WEIGHTS
The following tissues were prepared for microscopic examination: epididymides, ovaries, prostate, seminal vesicles, testes, uterus (horns and cervix), vagina. A microscopic examination was performed on the ovaries, testes and epididymides (with special emphasis on stages of spermatogenesis and histopathology of interstitial testicular cell structure) of all males and females in the control and high-dose groups. The body weights of the males were recorded before sacrifice and the testes and epididymides were weighed wet separately as soon as possible after dissection. The ratio of organ weight to body weight (recorded immediately before sacrifice) was calculated.

Postmortem examinations (offspring):

SACRIFICE
- The F1 offspring were sacrificed on day 5 post-partum.


GROSS NECROPSY
- A gross external examination before sacrifice was performed on all pups including those that died during lactation. There was no preservation of tissues.

Statistics:

Mean values were compared by one-way analysis of variance and Dunnett test. Percentage values were compared by the Fisher exact probability test.

CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS): In males, there were no deaths or clinical signs in the control group or in the 250 or 500 mg/kg bw/day groups. At 1000 mg/kg bw/day, one male was found dead on day 33 of the dosing period (no major factor contributing to death was established). At 1000 mg/kg bw/day, ptyalism was transiently observed in 4/11 males from days 20 or 21 of dosing. In females, there were no deaths in any group during the pre-mating period. During pregnancy, one female (E20403) given 250 mg/kg bw/day was found dead on day 10 post-coitum which was considered to be accidental and not related to the treatment. No clinical signs were recorded at 500 mg/kg bw/day during the pre-mating and pregnancy periods. At 250 mg/kg/day, regurgitation was observed during the pre-mating period in two females from days 22 to 24 or days 26 to 27, and in three other females for 1 or 3 consecutive days of the pregnancy period. At 1000 mg/kg/day, ptyalism was observed in 3/12 females on day 20 of the pre-mating period.


BODY WEIGHT AND FOOD CONSUMPTION (PARENTAL ANIMALS): The body weight change of all treated animals was unaffected by treatment. The food consumption of all the treated animals was similar to that of the controls.


REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS):
- The mating index were unaffected by the treatment. The pre-coital interval was similar in the control and the treated groups.
- All paired animals (except one pair at 250 and 500 mg/kg/day) mated within 1 to 4 days of cohabitation, i.e. within the duration of a single estrous cycle.
- The fertility index (pregnant/mated) ranged from 83.3% to 100%. The number of pregnant females was comparable within the groups (10/12, 10/12, 12/12, and 10/12 in the control, 250, 500 and 1000 mg/kg bw/day, respectively).
- The duration of gestation was similar in the control and the treated groups, and close to the normal value of 21 to 22 days.
- The gestation index (number of females with live born/number of pregnant female) ranged between 80% and 100%. Although the lowest value (80%) was slightly lower than historical control data (minimum = 90.9%; maximum = 100%), it was recorded in the low dose group only. As the gestation index calculated at 1000 mg/kg bw/day was similar (100%) to controls, the low value recorded in the low dose group was therefore considered to be of fortuitous origin. No difficulty at delivery was observed in any female.
- The number of corpora lutea and implantation sites were similar in the treated groups at all dose-levels. The post-implantation and neo-natal losses were low in the control and the treated groups and within the range of normal values.


ORGAN WEIGHTS (PARENTAL ANIMALS): no treatment related differences in organ weights were observed.


GROSS PATHOLOGY (PARENTAL ANIMALS): no treatment related abnormalities were observed.


HISTOPATHOLOGY (PARENTAL ANIMALS): no treatment related abnormalities were observed.

Dose descriptor:

NOAEL

Effect level:

>= 1 000 mg/kg bw/day (actual dose received)

Sex:

male/female

Basis for effect level:

other: no effects

VIABILITY (OFFSPRING): The number of pups which died during the four days of observation after birth was low (between 2 and 3.5%) and similar in all the groups. The viability index (pups surviving 4 days/number of liveborn) was comparable within the groups, within the range of Historical control data (mini = 95.9%, max = 100%) and was consequently considered to be unaffected by the treatment.


CLINICAL SIGNS (OFFSPRING): no treatment related clinical signs were observed.


BODY WEIGHT (OFFSPRING): The weights of pups were similar in the control and the treated groups on day 1 and day 4 post-partum.


SEX RATIO (OFFSPRING): The sex ratio was similar in the control and the treated groups, and close to a theoretical value of 50%.


GROSS PATHOLOGY (OFFSPRING): There were no gross external abnormalities in the control or treated groups.


HISTOPATHOLOGY (OFFSPRING): not done

Dose descriptor:

NOAEL

Generation:

F1

Effect level:

>= 1 000 mg/kg bw/day (actual dose received)

Sex:

male/female

Basis for effect level:

other: no effects

Reproductive effects observed:

not specified

Under the conditions of this study, the oral administration of Methanesulfonic Acid, at 250, 500 or 1000 mg/kg bw/day to male and female Sprague-Dawley rats, under the above detailed experimental conditions was well tolerated at all dose-levels. There were no substance-induced effects on the male and female reproductive performance, nor on the progeny of the parental rats up to 1000 mg/kg bw/day. Based on these results, the no observed adverse effect level (NOAEL) for parental toxicity and for toxic effect on reproductive performance and on progeny is 1000 mg/kg bw/day.

Effect on fertility: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

1 000 mg/kg bw/day

Species:

rat

Additional information

In a combined reproductive/developmental toxicity screening test (Chevron 2005), Sprague-Dawley rats were administered methane sulfonic acid (MSA) daily via gavage at 250, 500, or 1000 mg/kg bw/day. Males were dosed four weeks prior to mating, two weeks during the mating period and until sacrifice. Females were dosed four weeks prior to mating, two weeks during the mating period, through gestation (3 weeks), lactation until day 4 post partum (pp) and until sacrifice (day 5 pp). No mortality was seen. Clinical signs in males included ptyalism (excessive salivation) at 1000 mg/kg bw/ day. There were no treatment-related effects on body weights, organ weight changes or histopathology. MSA did not affect male and female reproductive performance or the progeny of the parental rats up to 1000 mg/kg bw /day. NOAEL (parental/reproductive toxicity) = 1000 mg/kg bw/day (based on no effects at highest dose tested).

Two-generation reproductive toxicity study does not need to be conducted because adequate data from the 28-days repeated dose study indicates no adverse effects on reproductive organs or tissues.

Short description of key information:
No effects for parental toxicity, reproductive performance and on progency were observed up to the highest dosage tested (1000 mg/kg/day) in a reproductive screening test, where rats were exposed to Methanesulphonic acid (70.5 % in water) by oral gavage.

Effects on developmental toxicity

Description of key information

No birth abnormalities were observed in the offspring of rats given a dosage of 400 mg/kg/day during days 6 through 15 of pregnancy in a pre-natal development toxicity study, where rats were exposed to Methanesulphonic acid (70.15 % in water) by oral gavage.

Link to relevant study records

Reference

Endpoint:

developmental toxicity

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: GLP Guideline study with acceptable restrictions (Not exposed until day prior to scheduled kill, no toxic effects of highest dose applied)

Qualifier:

according to guideline

Guideline:

OECD Guideline 414 (Prenatal Developmental Toxicity Study)

Deviations:

yes

Remarks:

Not exposed until day prior to scheduled kill, no toxic effects of highest dose applied

GLP compliance:

yes

Remarks:

Wil Research Laboratories

Species:

rat

Strain:

Sprague-Dawley

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Breeding Laboratories (Portage, Michigan)
- Age at study initiation: approx. 81 days
- Weight at study initiation: 266±9.5 g
- Housing: single
- Diet (e.g. ad libitum): Certified Rodent Labdiet, PMI Feeds Inc.
- Water (e.g. ad libitum): drinking water
- Acclimation period: 11 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): ca. 22
- Humidity (%): 44.5-61.2
- Air changes (per hr): 10
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: gavage

Vehicle:

water

Details on exposure:

VEHICLE
- Vehicle: deionized water
- Concentration in vehicle: 25, 25 and 50 mg/ml for the 25, 100 and 400 mg/kg bw/day groups, respectively
- Amount of vehicle (if gavage): 1, 4 and 8 ml/kg bw for the 25, 100 and 400 mg/kg bw/day groups, respectively

Analytical verification of doses or concentrations:

yes

Details on mating procedure:

- Impregnation procedure: cohoused (paired in the home cage of the male for mating)
- If cohoused:
- M/F ratio per cage: paired (1/1)
- Proof of pregnancy: sperm in vaginal smear day 0 of pregnancy

Duration of treatment / exposure:

GD 6 to 15

Frequency of treatment:

once daily

Duration of test:

up to GD 20

Remarks:

Doses / Concentrations:
25, 100 and 400 mg/kg bw
Basis:
actual ingested

No. of animals per sex per dose:

25 females

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: Based on dose range-finding developmental toxicity study on Methane Sulfonic Acid (MSA) in rats. MSA was orally administered to 5 groups of 8 rats once daily for GD 6-15 at dosage levels of 25, 50, 100, 200 and 300 mg/kg bw/day. No mortalities were observed. All maternal animals survived to the scheduled necropsy on GD 20. Rales, laboured respiration and gasping; findings of red material around the nose and/or mouth in the 100, 200, and 300 mg/kg bw/day groups. Slight mean body weight losses (2 to 5 g) and reduction in food consumption occured in the 100, 200 and 300 mg/kg bw/day groups during gestation days 6 to 9 when evaluated on a group mean basis. Mean body weights, gravid uterine weights, net body weights and net body weight gains were unaffected by the treatment at all dose levels. No treatment-related internal findings were observed at necropsy at any dose level. No effects were observed at any dose level on intrauterine growth and survival. No external developmental variations or malformations were observed in any of the fetuses in the treated groups.

Maternal examinations:

CLINICAL OBSERVATIONS: Yes
- Time schedule: twice a day, from day 0 through day 20

BODY WEIGHT: Yes
- Time schedule for examinations: on day 0, daily on day 6 to 16, and on day 20. Mean body weight changes were calculated for each corresponding interval and also for days 6-9, 9-12, 12-16, 6-16 and 0-20.

FOOD CONSUMPTION: Yes
- Time schedule: on day 0, daily on day 6 to 16, and on day 20

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day # 20
- Organs examined: Laparohysterectomy: uteri and ovaries, numbers of fetuses, early and late resorptions, total implantations and corpora lutea; mean gravid uterine weights and net body weight changes were calculated for each group; fetuses were weighed, sexed and examined for external, visceral and skeletal malformations and developmental variations.

Ovaries and uterine content:

The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
- Other: number of fetuses

Fetal examinations:

- External examinations: Yes: [all per litter]
- Soft tissue examinations: Yes: [all per litter]
- Skeletal examinations: Yes: [all per litter]
- Head examinations: No data

Statistics:

Chi-square test for fetal sex ratios; Fisher's Exact test for malformations and variations; Mann-whitney u-test for early and later resorptions, dead fetuses, postimplantation losses; One-way Anova with dunnett's test for maternal examinations and Kruskal-Wallis test for litter proportions of intrauterine data.

Details on maternal toxic effects:

Maternal toxic effects:no effects

Details on maternal toxic effects:
Clinical observations: No clinical signs that could be attributed to the test substance were observed in the treated groups. No mortality was observed until day 20 (necropsy). Body weight and food consumption were not affected by the treatment.
Necropsy: No treatment related internal findings were observed at any dose level. Intrauterine growth and survival were unaffected by test substance administration at all dose levels.

Dose descriptor:

NOAEL

Effect level:

>= 400 mg/kg bw/day

Basis for effect level:

other: maternal toxicity

Details on embryotoxic / teratogenic effects:

Embryotoxic / teratogenic effects:no effects

Details on embryotoxic / teratogenic effects:
Fetal external, soft tissue and skeletal malformations were observed in 0(0), 2(2), 2(2) and 1(1) fetuses (litters) in the control, 25, 100, and 400 mg/kg bw/day groups, respectively, and were considered to be spontaneous in origin. The developmental variations observed in the treated groups occurred similarly in the control group and/or in a manner which was not dose-related.

Dose descriptor:

NOAEL

Effect level:

>= 400 mg/kg bw/day

Basis for effect level:

other: teratogenicity

Abnormalities:

not specified

Developmental effects observed:

not specified

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

400 mg/kg bw/day

Species:

rat

Additional information

In the key study (ElfAtochem 1996) performed according to OECD Guideline 414 (Prenatal Developmental Toxicity Study), female rats (25/dose) were given daily oral gavage doses of 0, 25, 100 or 400 mg/kg bw/day of methanesulfonic acid (MSA) from gestation day 6 through 15 (GD6 -15). No test substance-related clinical signs or mortality were observed. No test substance-related developmental effects were observed. Based on the results of this study, the NOAEL was determined to be 400 mg/kg bw/day for maternal toxicity and developmental toxicity.

NOAEL (maternal and developmental toxicity) >= 400 mg/kg bw/day

In a second study (ElfAtochem 1996, range finder study), female rats (8/dose) were given daily oral gavage doses of 0, 25, 50, 100, 200 or 300 mg/kg bw/day of MSA from GD 5 through 15. Treatment-related clinical signs included rales, labored respiration and gasping, often correlated with findings of red material around the nose and/or mouth in the 100, 200 and 300 mg/kg bw/day groups. These findings appeared to be a function of the dosage concentration rather than the dose level, as they were observed with similar frequencies in the aforementioned groups, each of which received the test substance at a concentration of 50 mg/ml. Maternal toxicity was observed at dose levels of 100, 200 and 300 mg/kg bw/day (administered at a concentration of 50 mg/ml), as evidenced by changes in the clinical conditions of the animals and slight inhibition of body weight gain and food consumption during GD6 to 9. No maternal toxicity was observed at dose levels of 25 and 50 mg/kg bw/day (administered at a concentration of 25 mg/ml). No developmental toxicity was observed at dose levels up to 300 mg/kg bw/day.

NOAEL (maternal toxicity) = 50 mg/kg bw/day

LOAEL (maternal toxicity) = 100 mg/kg bw/day (based on clinical observations, body weight and food consumption)

NOAEL (developmental toxicity) >= 300 mg/kg bw/day (highest dose-level tested)

Justification for classification or non-classification

Based on the available data, the test substance is not classified with regard to toxicity to reproduction according to Directive 67/548/EEC (DSD) and Regulation (EC) No 1272/2008 (CLP), respectively.