1-o-tolylbiguanide

Endpoint summary

Description of key information

Key study on eye irritation shows that OTB is moderately irritating.  

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Justification for type of information:

Animal testing pre-dates availablity of valid in-vitro methods

Qualifier:

according to guideline

Guideline:

other: Appraisal of the Safety of Chemicals in Food, Drugs and cosmetics (1959), the US Association of Food and Drug Officials (AFDO)

Principles of method if other than guideline:

The procedure used was the patch test technique described in the above guideline.

GLP compliance:

no

Species:

rabbit

Strain:

Himalayan

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Weight at study initiation: 1.5 - 2.0 Kg
- Housing: housed individually in metal cages
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 8 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): constant room temperature of 18 +/- 1° C
- Humidity (%): 55 +/- 5 %
- Photoperiod (hrs dark / hrs light): 10 hours dark / 14 hours light

Type of coverage:

occlusive

Preparation of test site:

abraded

Vehicle:

not specified

Controls:

not specified

Duration of treatment / exposure:

The patches were covered with an impermeable material and were fastened to the body of the rabbit with adhesive tape. The dressings were removed after a 24 hour exposure.

Observation period:

The skin irritation was scored immediately and 48 hours after removal of the dressings (24 and 72 hours after initiation of treatment)

Number of animals:

6 (3 male, 3 female)

Irritation parameter:

overall irritation score

Basis:

mean

Time point:

24 h

Score:

ca. 0.2

Max. score:

2

Reversibility:

fully reversible

Irritant / corrosive response data:

Only limited details were avbailable, but conclusion considered to be reliable in that the substance is only slightly irritant.

The skin irritation was scored immediately and 48 hours

after removal of the dressings   (24 and 72 hours after initiation of treatment)• Skin irritation was scored in accordance with the irritation score from table 1.

The severity of skin irritation was rated as follows: A mean value of less than 2 indicated mild, from 2 to 5 moderate and above 6 severe skin irritation.

Score for skin irritation in rabbits (Table 1)

Erythema and eschar formation

No erythema....................................0

Very slight erythema (barely perceptible)......1

Well defined erythema..........................2

Moderate to severe erythema.................. 3

Severe erythema (beet redness) to slight eschar

formation (injuries in depth)............... 4

Maximum possible erythema score

Edema formation

No edema..................................... 0

Very slight edema (barely perceptible)....... 1

Slight edema (edges of area well defined by

definite raising)............................ 2

Moderate edema (raised approximately 1 mm)... 3

Severe edema (raised more than 1 mm and

extending beyond area of exposure)........... 4

Maximum possible edema score4

Results - Table 2

The primary irritation index is the mean value of the sum of the scores for erythema and edema from all 6 rabbits 24 and 72 hours after initiation of treatment. The maximum possible score is 8.

The primary skin irritation index in this experiment was established to be 0.2.

Skin irritation in individual rabbits - Table 2

Animal No. Sex	Skin Reaction	24 hrs after application		72 hrs after application
		intact skin	scarified skin	intact skin	scarified skin
1♂	Erythema	0	1	0	0
	Edema	0	0	0	0
2♂	Erythema	0	0	0	0
	Edema	0	0	0	0
3♂	Erythema	0	1	0	0
	Edema	0	1	0	0
4♀	Erythema	0	1	0	0
	Edema	0	0	0	0
5♀	Erythema	0	0	0	0
	Edema	0	0	0	0
6♀	Erythema	0	0	0	0
	Edema	0	0	0	0

Interpretation of results:

not irritating

Remarks:

Migrated information

Conclusions:

Average score of 0.2 suggests the material is not irritating to skin.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

comparable to guideline study with acceptable restrictions

Justification for type of information:

Animal testing pre-dates availablity of valid in-vitro methods
Full data set not seen, but conclusions demonstrate eye irritation

Guideline:

other: "Appraisal of the Safety of Chemicals in Foods, Drugs and Cosmetics" (1959), the US Association of Food and Drug Officials (AFDO)

GLP compliance:

not specified

Species:

rabbit

Strain:

Himalayan

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Weight at study initiation: 1.5-2.0 Kg
- Housing: metal cages
- Diet (e.g. ad libitum): ad libitum access to standard rabbit food - NAFAG, Gossau SG
- Water (e.g. ad libitum): ad ibitum
- Acclimation period: 8 days
- Only rabbits with normal ophthalmic findings were used for these tests.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18 +/-1°C
- Humidity (%): 55+/-5%
- Photoperiod (hrs dark / hrs light): 14 hours light, 10 hours dark

Vehicle:

unchanged (no vehicle)

Controls:

other: The right eye was not treated and served as an untreated control.

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.1g

Duration of treatment / exposure:

In 3 of the 6 rabbits approximately 30 seconds after treatment the treated eye was flushed with 10 ml of lukewarm water.

Observation period (in vivo):

The eye irritation was appraised with a slit-lamp on day 1, 2, 3, 4 and 7

Number of animals or in vitro replicates:

6 (3 male, 3 female)

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing (if done): In 3 of the 6 rabbits approximately 30 seconds after treatment the
treated eye was flushed with 10 ml of lukewarm water.

SCORING SYSTEM:
Score for eye irritation in rabbits (Table 1)
CORNEA:
A: Opacity and degree of density (most dense area scored)
-No opacity 0
-Scattered or diffuse area, details of iris clearly visible 1
-Easily discernible translucent areas, details of iris slightly obscured 2
-Opalescent areas, no details of iris visible, size of pupil barely discernible 3
-Opaque, iris invisible 4
B: Area of cornea involved
-One quarter (or less) but not zero 1
-Greater than one quarter, but less than half 2
-Greater than half, but less than three quarters 3
-Greater than three quarters, up to whole area 4
A x B x 5 Maximum possible score = 80
IRIS:
A: Values
Normal 0
Folds above normal, congestion, swelling, circumcornea injection (any or all of these or
combination of any thereof) iris still reacting to light (sluggish reaction is positive 1
No reaction to light, hemorrhage, gross destruction (any or all of these) 2
A x 5 Maximum possible score = 10
CONJUNCTIVAE:
A: Redness (refers to palpebral and bulbar conjunctivae excluding cornea and iris)
Vessels normal 0
Vessels definitely injected above normal 1
More diffuse, deeper crimson red, individual vessels not easily discernible 2
Diffuse beefy red 3
B: Cheraosis
No swelling 0
Any swelling above normal (includes nictitating membrane) 1
Obvious swelling with partial eversion of lids 2
Swelling with lids about half closed 3
Swelling with lids about half closed to completely closed 4
C: Discharge
No discharge 0
Any amount different from normal (does not include small amounts observed in inner
canthus of normal animals) 1
Discharge with moistening of the lids and hairs just adjacent to lids 2
Discharge with moistening of the lids and hairs, and considerable area around the eye 3
(A + B + C) x 2 Maximum possible score = 20

TOOL USED TO ASSESS SCORE: hand-slit lamp

Irritation parameter:

overall irritation score

Basis:

mean

Time point:

24/48/72 h

Score:

15.6

Max. score:

110

Reversibility:

not specified

Remarks on result:

probability of moderate irritation

Irritation parameter:

cornea opacity score

Basis:

mean

Time point:

24/48/72 h

Score:

5

Max. score:

80

Reversibility:

not specified

Remarks on result:

probability of moderate irritation

Irritation parameter:

iris score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

10

Reversibility:

not specified

Remarks on result:

no indication of irritation

Irritation parameter:

conjunctivae score

Basis:

mean

Time point:

24/48/72 h

Score:

10.6

Max. score:

20

Reversibility:

not specified

Remarks on result:

probability of moderate irritation

Irritation parameter:

chemosis score

Basis:

mean

Time point:

24/48/72 h

Score:

10.6

Max. score:

20

Remarks on result:

probability of moderate irritation

Irritant / corrosive response data:

Full data set not seen, but conclusions demonstrate eye irritation

The total maximum score was thus 80 for the cornea, 10 for the iris, 20 for the conjunctivae and 110 for the entire eye. The severity of overall eye irritation was rated as:

0 -10          minimal

11 -25         slight

26 -56         moderate

57 -84         marked

above 84     extreme

Results - Tables 2 and 3

In the present experiments the irritation index was established as 20 for the cornea, 1.8 for the iris and 7.8 for the conjunctivae. The substance causes therefore a moderate overall eye irritation.

Table 2 Eye irritation in individual rabbits with eyes rinsed 30 seconds after treatment

Days after appl.	Rabbit 1 ♀			Rabbit 2 ♀			Rabbit 3 ♀
	Cornea	Iris	Conjunct.	Cornea	Iris	Conjunct.	Cornea	Iris	Conjunct.
1	15	0	10	10	0	10	0	0	0
2	10	0	10	10	0	8	0	0	0
3	10	0	8	15	0	8	0	0	0
4	10	0	8	15	0	8	0	0	0
7	5	0	8	5	0	6	0	0	0

Table 3 Eye irritation in individual rabbits with eyes not rinsed after treatment

Days after appl.	Rabbit 4 ♂			Rabbit 5 ♂			Rabbit 6 ♂
	Cornea	Iris	Conjunct.	Cornea	Iris	Conjunct.	Cornea	Iris	Conjunct.
1	5	0	12	30	0	14	60	10	12
2	5	0	12	30	0	14	60	10	12
3	5	0	8	30	0	12	60	10	10
4	5	0	6	30	5	10	60	10	10
7	5	0	0	30	5	10	80	10	10

Interpretation of results:

Category 2 (irritating to eyes) based on GHS criteria

Remarks:

Migrated information Criteria used for interpretation of results: other: "Appraisal of the Safety of Chemicals in Foods, Drugs and Cosmetics" (1959), the US Association of Food and Drug Officials (AFDO).

Conclusions:

moderately irritating
Animal testing pre-dates availablity of valid in-vitro methods
Full data set not seen, but conclusions demonstrate eye irritation

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

The eye irritation study on rabbits shows that OTB is moderately irritating. The eye irritation was calculated on the basis of a score of 110 for the entire eye, with the score of anything between 26 -56 being moderately irritating to the eye. From this study of 3 rabbits a mean score of 29.6 was obtained which fits into this boundary.

Effects on eye irritation: Eye Irrit 2