Registration Dossier

Two guideline studies are available to evaluate the irritant properties of MTSC : skin irritation (OECD 404) and eye irritation (OECD 405).
The results showed that MTSC is not irritant for skin but slightly irritant for eye. MTSC is not classified for these two endpoints according to the regulation EC no.1272/2008.

Reference

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2001-04-03 to 2001-04-08

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP Guideline study (OECD 404)

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

yes

Remarks:

Minor deviations were not considered to have compromised the validity or integrity of the study : the relative humidity recorded in the animal room was sometimes outside of the target ranges ; the animals were given 110 pelleted

GLP compliance:

yes

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
-Sex: male
- Source: CEGAV (Saint Mars d'Egrenne, France)
- Age at study initiation: no data
- Weight at study initiation: 2.6 ± 0.5 kg
- Housing: individually in polystyrene cages
- Diet (e.g. ad libitum): free access to 110 pelleted diet (UAR, Villemoisson, Epinay¬sur-Orge, France).
- Water (e.g. ad libitum): Drinking water filtered by a FG Millipore membrane (0.22 micron) was provided ad libitum
- Acclimation period: at least 5 days before the beginning of the study

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18 ± 3°C
- Humidity (%): 30 to 70%
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): 12/12

Type of coverage:

semiocclusive

Preparation of test site:

other: clipped using electric clippers

Vehicle:

other: none

Controls:

not required

Amount / concentration applied:

undiluted
Purified water (prepared at CIT by reverse osmosis) was used in order to moisten the test substance and ensure a good contact with the skin.

Duration of treatment / exposure:

4 hour(s)

Observation period:

3 days (because no effect were observed at 72 hours)

Number of animals:

3

Details on study design:

ADMINISTRATION:
- Area of exposure: left flank (3-minute exposure) and right flank (4-hour exposure)
- Total quantity applied: 500 mg
- Administration frequency: once
- Removal of test substance: residual is wiped with a dry gauze pad
EXAMINATIONS:
- Scoring system: Draize's score
- Examination time points: 1h, 24 h, 48 h and 72 hours after the patch removal.

Irritation parameter:

erythema score

Basis:

mean

Remarks:

3 rabbits

Time point:

other: 24-48-72 hours

Score:

0.1

Max. score:

4

Reversibility:

fully reversible within: 48 hours

Remarks on result:

other: Scores of 3 rabbits were: 0.3, 0.0 and 0.0

Irritation parameter:

edema score

Basis:

mean

Remarks:

3 rabbits

Time point:

other: 24-48-72 hours

Score:

0

Max. score:

4

Remarks on result:

other: Scores of 3 rabbits were 0.0

Irritant / corrosive response data:

After a 3-minute exposure: No cutaneous reaction were noted in any rabbits.
After a 4-hour exposure: A very slight erythema (grade 1) was observed in one rabbit at 1h and 24h after patch removal. This erythema disappeared thereafter. Other rabbits did not exhibit any cutaneous reactions.

Other effects:

none

Table : individual cutaneous examinations and mean values of the scores recorded at each reading (24, 48 and 72 hours) for each animal (application for 4 hours)

Rabbit number	Dermal irritation	scores				Mean irritation score (1)
Rabbit number	Dermal irritation	1h (D1)	24h (D2)	48h (D3)	72h (D4)	Mean irritation score (1)
993	Erythema	1	1	0	0	0.3
	Oedema	0	0	0	0	0.0
	Other	*	*	*	*
578	Erythema	0	0	0	0	0.0
	Oedema	0	0	0	0	0.0
	Other	*	*	*	*
993	Erythema	0	0	0	0	0.0
	Oedema	0	0	0	0	0.0
	Other	*	*	*	*

(1) mean of scores on days 2, 3 and 4

* : none

D = day, h = hour

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: other: Regulation EC no.1272/2008

Conclusions:

Under these experimental conditions, the test substance MTSC is non-irritant when applied topically to rabbits.

Executive summary:

The potential of the test substance MTSC to induce skin irritation was evaluated in rabbits according to OECD 404 and in compliance with the principles of Good Laboratory Practice Regulations.

In the first instance, the test substance was applied for periods of 3 minutes and 4 hours to a single male New Zealand White rabbit. Since the test substance was not severely irritant on this first animal, it was then applied for 4 hours to two other animals. A single dose of 500 mg of the test substance in its original form was applied to the closelyclipped skin of one flank. The test substance was held in contact with the skin by means of a semi-occlusive dressing. Cutaneous reactions were observed approximately 1 hour, 24, 48 and 72 hours after removal of the dressing.

After a 3-minute exposure (one animal): No cutaneous reactions were observed.

After a 4-hour exposure (three animals): A very slight erythema was noted in one animal on days 1 and 2. No other cutaneous reactions were observed.

Mean scores over 24, 48 and 72 hours for each animal were 0.3, 0.0 and 0.0 for erythema and 0.0, 0.0 and 0.0 for oedema.

Under these experimental conditions, the test substance MTSC is non-irritant when applied topically to rabbits.

Endpoint conclusion:

no adverse effect observed (not irritating)

Reference

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 2001-04-10 to 2001-04-30

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP Guideline study (OECD 405)

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

yes

Remarks:

minor deviations were not considered to have compromised the validity or integrity of the study : relative humidity, animal breeder's and diet.

GLP compliance:

yes

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
-Sex: male
- Source: CEGAV (Saint Mars d'Egrenne, France)
- Age at study initiation: no data
- Weight at study initiation: 2.6 ± 0.3 kg
- Housing: individually in polystyrene cages
- Diet (e.g. ad libitum): free access to 110 pelleted diet (UAR, Villemoisson, Epinay¬sur-Orge, France).
- Water (e.g. ad libitum): Drinking water filtered by a FG Millipore membrane (0.22 micron) was provided ad libitum
- Acclimation period: at least 5 days before the beginning of the study

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18 ± 3°C
- Humidity (%): 30 to 70%
- Air changes (per hr): no data
- Photoperiod (hrs dark / hrs light): 12/12

Vehicle:

unchanged (no vehicle)

Controls:

other: yes, untreated eye

Amount / concentration applied:

undiluted ; The test substance was used in its original form.
Amount applied: 100 other: mg

Duration of treatment / exposure:

a single exposure

Observation period (in vivo):

6 days (because no effect was observed at day 6)

Number of animals or in vitro replicates:

3 rabbits

Details on study design:

Comment: not rinsed

EXAMINATIONS:
- Ophthalmoscopic examination: Yes
- Scoring system: Draize's scale
- Observation period: 1h, 24h, 48h and 72h after administration of the test substance
- Tool used to assess score: fluorescein

Irritation parameter:

conjunctivae score

Remarks:

(chemosis)

Basis:

mean

Remarks:

3 rabbits

Time point:

other: 24-48-72 hours

Score:

0.87

Max. score:

4

Reversibility:

fully reversible within: 5 days

Remarks on result:

other: Individual scores were : 1.3, 1.0 and 0.3

Irritation parameter:

conjunctivae score

Remarks:

(redness)

Basis:

mean

Remarks:

3 rabbits

Time point:

other: 24-48-72 hours

Score:

1.47

Max. score:

3

Reversibility:

fully reversible within: 6 days

Remarks on result:

other: Individual scores were : 1.7, 1.0 and 1.7

Irritation parameter:

conjunctivae score

Remarks:

(discharge)

Basis:

mean

Remarks:

6 rabbits

Time point:

other: 24-48-72 hours

Score:

0.2

Max. score:

3

Reversibility:

fully reversible within: 48 hours

Remarks on result:

other: Individual scores were: 0.3, 0.3 and 0.0

Irritation parameter:

iris score

Basis:

mean

Remarks:

3 rabbits

Time point:

other: 24-48-72 hours

Score:

0.1

Max. score:

2

Reversibility:

fully reversible within: 48 hours

Remarks on result:

other: Individually scores were: 0.3, 0.0 and 0.0

Irritation parameter:

cornea opacity score

Remarks:

(intensity)

Basis:

mean

Remarks:

3 rabbits

Time point:

other: 24-48-72 hours

Score:

0.43

Max. score:

4

Reversibility:

fully reversible within: 5 days

Remarks on result:

other: Individually scores were: 1.3, 0.0 and 0.0

Irritation parameter:

cornea opacity score

Remarks:

(area)

Basis:

mean

Remarks:

3 rabbits

Time point:

other: 24-48-72 hours

Score:

0.43

Max. score:

4

Reversibility:

fully reversible within: 5 days

Remarks on result:

other: Individually scores were: 1.3, 0.0 and 0.0

Irritant / corrosive response data:

Very slight or slight conjunctival reactions were observed in an animals from day 1: a very slight or slight chemosis (grade 1 or 2), a very slight or slight redness of the conjunctiva (grade 1 or 2) and a clear discharge were noted. Some of the se reactions persisted up to day 5 at the latest. A slight iritis (grade 1) was noted in one animal, on day 2 only. A very slight or slight corneal opacity (grade 1 or 2) was recorded in the same animal, from day 2 up to day 4. Mean scores calculated for each animal over 24, 48 and 72 bourg were 1.3, 1.0 and 0.3 for chemosis, 1.7, 1.0 and 1.7 for redness of the conjunctiva, 0.3, 0.0 and 0.0 for iris lesions and 1.3, 0.0 and 0.0 for comeal opacity.

Other effects:

none

Table 1: Individual ocular examinations and mean values of the scores recorded at each reading (24, 48 and 72 hours) for each animal

Rabbit number	Region of eye	Description of ocular reactions	scores						Mean irritation score (1)
Rabbit number	Region of eye	Description of ocular reactions	1h (D1)	24h (D2)	48h (D3)	72h (D4)	(D5)	(D6)	Mean irritation score (1)
993	conjunctivae	Chemosis	1	2	1	1	0	-	1.3
		Redness	1	2	2	1	0	-	1.7
		Discharge	1	1	0	0	0	-	0.3
	Iris		0	1	0	0	0	-	0.3
	Corneal opacity	Intensity	0	2	1	1	0	-	1.3
	Corneal opacity	Area	0	2	1	1	0	-	1.3
	Other		*	*	*	*	*	-
	Fluorescein		/	U	U	U	U	-
579	conjunctivae	Chemosis	1	1	1	1	0	-	1.0
		Redness	1	1	1	1	0	-	1.0
		Discharge	1	1	0	0	0	-	0.3
	Iris		0	0	0	0	0	-	0.0
	Corneal opacity	Intensity	0	0	0	0	0	-	0.0
	Corneal opacity	Area	0	0	0	0	0	-	0.0
	Other		*	*	*	*	*	-
	Fluorescein		/	U	/	/	/	-
566	conjunctivae	Chemosis	2	1	0	0	0	0	0.3
		Redness	2	2	2	1	1	0	1.7
		Discharge	1	0	0	0	0	0	0.0
	Iris		0	0	0	0	0	0	0.0
	Corneal opacity	Intensity	0	0	0	0	0	0	0.0
	Corneal opacity	Area	0	0	0	0	0	0	0.0
	Other		Su	*	*	*	*	*
	Fluorescein		/	U	/	/	/	/

(1) mean of scores on days 2, 3 and 4

* : none

U: fluorescein batch No.D616

/: fluorescein not used

Su: residual test substance

- : ocular examination not performed

Interpretation of results:

slightly irritating

Remarks:

Migrated information but not classified Criteria used for interpretation of results: other: Regulation EC n°1272/2008

Conclusions:

Under these experimental conditions, the test substance 4 -methylthiosemicarbazide is slightly irritant when administered by ocular route to rabbits.

Executive summary:

The potential of the test substance 4 -methylthiosemicarbazide to induce ocular irritation was evaluated in rabbits according to OECD 405 and with the principles of Good Laboratory Practice Regulations.

A single dose of 100 mg of the test substance in its original form was introduced into the left conjunctival sac of three male New Zealand White rabbits. The right eye was not treated andserved as control. The eyes were not rinsed after administration of the test substance. Ocular reactions were observed approximately 1 hour, 24, 48 and 72 hours after the administration and then daily until reversibility of the ocular reactions. The mean values of the scores for chemosis, redness of the conjunctiva, iris lesions and corneal opacity were calculated for each animal.

Very slight or slight conjunctival reactions (very slight or slight chemosis, very slight or slight redness of the conjunctiva and clear discharge) were observed in all animals from day 1: some of these reactions persisted up to day 5 at the latest.

A slight iritis was noted in one animal, on day 2 only. A very slight or slight corneal opacity was recorded in the same animal, from day 2 up to day 4.

Mean scores calculated for each animal over 24, 48 and 72 hours were 1.3, 1.0 and 0.3 forchemosis, 1.7, 1.0 and 1.7 for redness of the conjunctiva, 0.3, 0.0 and 0.0 for iris lesions and 1.3,0.0 and 0.0 for corneal opacity.

Under these experimental conditions, the test substance 4 -methylthiosemicarbazide is slightly irritant when administered by ocular route to rabbits.

Endpoint conclusion:

no adverse effect observed (not irritating)

Endpoint conclusion:

no study available

Skin irritation (Manciaux 2001) : The potential of the test substance MTSC to induce skin irritation was evaluated in rabbits according to OECD 404 and in compliance with the principles of Good Laboratory Practice Regulations.

In the first instance, the test substance was applied for periods of 3 minutes and 4 hours to a single male New Zealand White rabbit. Since the test substance was not severely irritant on this first animal, it was then applied for 4 hours to two other animals. A single dose of 500 mg of the test substance in its original form was applied to the closelyclipped skin of one flank. The test substance was held in contact with the skin by means of a semi-occlusive dressing. Cutaneous reactions were observed approximately 1 hour, 24, 48 and 72 hours after removal of the dressing.

After a 3-minute exposure (one animal):No cutaneous reactions were observed.

After a 4-hour exposure (three animals):A very slight erythema was noted in one animal on days 1 and 2.No other cutaneous reactions were observed.

Mean scores over 24, 48 and 72 hours for each animal were 0.3, 0.0 and 0.0 for erythema and 0.0, 0.0 and 0.0 for oedema.

Under these experimental conditions, the test substance MTSC is non-irritant when applied topically to rabbits.

Eye irritation (Manciaux 2001) : The potential of the test substance 4 -methylthiosemicarbazide to induce ocular irritation was evaluated in rabbits according to OECD 405 and with the principles of Good Laboratory Practice Regulations. A single dose of 100 mg of the test substance in its original form was introduced into theleft conjunctival sac of three male New Zealand White rabbits. The right eye was not treated and served as control. The eyes were not rinsed after administration of the test substance. Ocular reactions were observed approximately 1 hour, 24, 48 and 72 hours after the administration and then daily until reversibility of the ocular reactions. The mean values of the scores for chemosis, redness of the conjunctiva, iris lesions and corneal opacity were calculated for each animal. Very slight or slight conjunctival reactions (very slight or slight chemosis, very slight or slight redness of the conjunctiva and clear discharge) were observed in all animals from day 1: some of these reactions persisted up to day 5 at the latest. A slight iritis was noted in one animal, on day 2 only. A very slight or slight corneal opacity wasrecorded in the same animal, from day 2 up to day 4. Mean scores calculated for each animal over 24, 48 and 72 hours were 1.3, 1.0 and 0.3 forchemosis, 1.7, 1.0 and 1.7 for redness of the conjunctiva, 0.3, 0.0 and 0.0 for iris lesions and 1.3,0.0 and 0.0 for corneal opacity. Under these experimental conditions, the test substance 4 -methylthiosemicarbazide is slightly irritant when administered by ocular route to rabbits.

Justification for selection of skin irritation / corrosion endpoint:
Only one study is available for this endpoint.

Justification for selection of eye irritation endpoint:
Only one study is available for this endpoint.

Effects on eye irritation: slightly irritating

Proposed self-classification

- Regulation (EC) No 1272/2008 :Not classified

- Directive 67/548/EEC :Not classified