Methanesulphonic acid

Toxicity to reproduction

Administrative data

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

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2005

Report date:

2005

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 421 (Reproduction / Developmental Toxicity Screening Test)

GLP compliance:

yes

Remarks:

CIT Research Laboratories, France

Test material

Test material information

Constituent 1

Reference substance name:

Methanesulphonic acid

EC Number:

200-898-6

EC Name:

Methanesulphonic acid

Cas Number:

75-75-2

Molecular formula:

CH4O3S

IUPAC Name:

methanesulfonic acid

Details on test material:

- Name of test material (as cited in study report): Methanesulfonic acid
- Physical state: colorless liquid
- Analytical purity: 70.50
- Composition of test material, percentage of components: Methanesulfonic acid 70 % in water
- Lot/batch No.: 4810A
- Storage condition of test material: keep hermetically closed, at room temperature, in a well ventilated place

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 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

Administration / exposure

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

Doses / concentrations

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.

Examinations

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.

Results and discussion

Results: P0 (first parental generation)

Details on results (P0)

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.

Effect levels (P0)

Dose descriptor:

NOAEL

Effect level:

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

Sex:

male/female

Basis for effect level:

other: no effects

Results: F1 generation

Details on results (F1)

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

Effect levels (F1)

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

Overall reproductive toxicity

Reproductive effects observed:

not specified

Any other information on results incl. tables

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.