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Diss Factsheets

Administrative data

Endpoint:
phototoxicity
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: Well-conducted scientific study to GLP

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2003
Report date:
2003

Materials and methods

Test guideline
Qualifier:
no guideline required
Principles of method if other than guideline:
Study of potential for photoxicity and photoallergy by dermal route in guinea pigs by method of Unkovic (1983).
GLP compliance:
yes (incl. QA statement)
Type of method:
in vivo

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: very viscous colorless gel
Details on test material:
- Name of test material (as cited in study report): Isobornylcyclohexanol
- Analytical purity: 100%
See confidential details on test material for more information

Test animals

Species:
guinea pig
Strain:
Hartley
Remarks:
Crl: (HA) BR
Sex:
male
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Charles River Laboratories, France
- Age at study initiation: 1-2 months
- Weight at study initiation: 489 +/- 28 g
- Fasting period before study: not applicable
- Housing: individually in polycarbonate cages with stainless steel lid (48 cm x 27 cm x 20 cm) equipped with a polypropylene bottle.
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 +/- 2
- Humidity (%): 30-70
- Air changes (per hr): 12 cycles/hour of filtered, non-recycled air.
- Photoperiod (hrs dark / hrs light): 12h/12h

IN-LIFE DATES: Main study: From: 12 June 2003 to 1 August 2003

Administration / exposure

Route of administration:
dermal
Vehicle:
other: diethyl phthalate
Details on exposure:
PREPARATION OF DOSING SOLUTIONS:
The test item was prepared at the chosen concentrations in the appropriate vehicle. All preparations were made freshly on the morning of administration and any unused material was discarded that same day.

VEHICLE
- Justification for use and choice of vehicle (if other than water): The test item was not soluble in purified water and in ethanol/water (80/20, w/w). The test item was soluble in acetone, acetone/olive oil (4/1, v/v) and diethylphtalate: homogeneous dosage form preparations were obtained, whatever the proportion in the first two vehicles and a homogeneous solution was obtained at the maximum concentration of 25% in diethylphtalate. According to the results of the preliminary test (see § 3.2) and at the
request of the Sponsor, the vehicle retained for the main test was diethylphtalate.
- Concentration in vehicle: 5%
- Lot/batch no. (if required): batch No. U02011 (Sigma, Saint Quentin Fallavier, France).
Duration of treatment / exposure:
Phototoxicity: 1 exposure (24 hours)
Photoallergy: 6 induction applications, 1 challenge application
Frequency of treatment:
Photoallergy: 6 applications over 8 days
Post exposure period:
Photoallergy: 20 days between induction & challenge
Doses / concentrations
Dose / conc.:
5 other: % (nominal conc.)
No. of animals per sex per dose:
5 or 10
Control animals:
yes, concurrent vehicle
yes, sham-exposed
yes, historical
Details on study design:
See below

Examinations

Examinations:
CLINICAL EXAMINATIONS
Morbidity and mortality: The animals were checked at least once a day for mortality or signs of morbidity.
Clinical signs: The animals were observed at least once a day for clinical signs.
Body weight: The animals were weighed individually on the day of allocation into the groups, on the first day of the study (day 1) and on the last day of the study (day 31).

PATHOLOGY
Necropsy: At the end of the study, all the animals were killed by carbon dioxide asphyxiation.
No necropsy was performed.
Skin samples: No skin samples were taken.
Positive control:
8-Methylpsoralen, Phenothiazine

Results and discussion

Details on results:
Phototoxicity: A questionable to moderate erythema was noted in all animals of groups 1, 2, 3 and 4 at the 1 and 4-hour readings. These cutaneous reactions decreased in intensity (questionable or discrete erythema) in almost all animals of all groups on day 2. As these cutaneous reactions were of similar intensity and incidence in animals of all groups on days 1 and 2, they could not be attributed to a phototoxic effect of the test item.
Photoallergy: In the control group 1 (irradiated only), the few cutaneous reactions observed remained within the range of a local reaction at an infra-erythematogenic irradiation dose. In the control group 2 (treated only), a discrete erythema was noted in 4/5 and 2/5 animals at the 4 and 24-hour readings, respectively.
In the treated group 3 (treated and irradiated), a questionable or discrete erythema was recorded in 8/10, 9/10, 7/10 and 2/10 animals at the 1, 4, 24 and 48-hour readings, respectively. In the control group 4 (treated with the vehicle and irradiated), a questionable or discrete erythema was observed in 4/5, 4/5, 3/5 and 1/5 animals at the 1, 4, 24 and 48-hour readings, respectively. No cutaneous reactions which could be attributed to a photoallergenic effect of the test item
were observed.

Any other information on results incl. tables

Clinical examinations / Body weight::

No clinical signs and no deaths occurred during the study. The body weight gain of the treated animals was similar to that of the control animals.

Table n°1: Evaluation of phototoxic reactions on days 1 and 2.

Scoring of skin reactions was as follows:

 

Group

Animal number

Before treatment

Day 1

1 hour

Day 1

4 hours

Day 2

24 hours

1

111

0

1

1

0

Irradiation

112

0

0.5

0.5

0.5

 

113

0

0.5

0.5

0.5

 

114

0

0.5

0.5

0

 

115

0

1

1

0

2

116

0

0

1

0

Test item

117

0

1

2

1

 

118

0

1

1

1

 

119

0

1

1

1

 

120

0

1

2

1

3

121

0

1

1

0

Test item

122

0

1

1

0.5

and irradiation

123

0

1

1

0

 

124

0

0.5

0.5

0

 

125

0

1

1

0

 

126

0

0.5

1

0.5

 

127

0

0.5

1

0.5

 

128

0

1

1

1

 

129

0

1

2

1

 

130

0

1

2

0.5

4

131

0

0.5

0.5

0

Vehicle

132

0

0.5

1

0.5

and irradiation

133

0

0.5

1

0.5

 

134

0

0.5

0.5

0.5

 

135

0

1

1

0

 

Evaluation of cutaneous reactions from day 3 to day 9: A questionable or discrete erythema (grade 0.5 or 1), sometimes together with dryness of the skin, was noted in almost all animals of the control groups 2 and 4. A questionable to moderate erythema (grades 0.5 to 2), sometimes together with dryness of the skin, was recorded in almost all animals of the control group 1 and treated group 3.

Table n°2: Evaluation of photoallergenic reactions from day 29 to day 31 / Scoring of skin reactions was as follows:

Group

Animal number

Before

treatment

Day 29

1 hour

Day 29

4 hours

Day 30

24 hours

Day 31

48 hours

 

 

LF

RF

LF

RF

LF

RF

LF

RF

LF

RF

1

111

0

0

0.5

0.5

0.5

0.5

0.5

0.5

0

0

Irradiation

112

0

0

0

0.5

0.5

0.5

0

0

0

0

 

113

0

0

0.5

0.5

0.5

0.5

0

0

0

0

 

114

0

0

0

0

0.5

0.5

0

0

0

0

 

115

0

0

0

0

0

0

0

0

0

0

2

116

0

0

0

0

0

0

0

0

0

0

Test item

117

0

0

0

0

1

1

0

0

0

0

 

118

0

0

0

0

1

1

0

0

0

0

 

119

0

0

0

0

1

0

1

0

0

0

 

120

0

0

0

0

1

1

1

1

0

0

 

3

 

121

 

0

 

0

 

0.5

 

1

 

1

 

1

 

1

 

1

 

0

 

1

Test item

122

0

0

0

0.5

0

0.5

0

0.5

0

0

and

123

0

0

0.5

1

0.5

1

0

0

0

0

irradiation

124

0

0

0.5

0.5

1

0.5

0

0

0

0

 

125

0

0

0

0

0.5

0.5

0.5

0.5

0

0

 

126

0

0

0.5

0.5

0.5

0.5

0

0.5

0

0

 

127

0

0

0

0

0

0

0

0

0

0

 

128

0

0

0

0.5

0

0.5

0

0.5

0

0

 

129

0

0

0.5

0.5

1

1

0.5

0.5

0.5

0.5

 

130

0

0

1

1

1

1

1

1

0

0

 

4

 

131

 

0

 

0

 

0

 

0

 

0

 

0

 

0

 

0

 

0

 

0

Vehicle

132

0

0

0

0.5

0

0.5

0

0

0

0

and

133

0

0

0.5

1

0.5

1

0

1

0

0

irradiation

134

0

0

0.5

0.5

0.5

0.5

0.5

0.5

0.5

0

 

135

0

0

0.5

0.5

1

0.5

0.5

0.5

0

0

 

LF : left flank (UV B)

RF : right flank (UV A)

Applicant's summary and conclusion

Conclusions:
Under our experimental conditions, topical applications of the test item Isobornylcyclohexanol followed by UV irradiation do not induce any phototoxic or photoallergenic reactions in guinea pigs.
Executive summary:

The phototoxic and photoallergenic potential of the test item Isobornylcyclohexanol was evaluated by cutaneous route in guinea pigs. Twenty-five male Dunkin-Hartley guinea pigs were allocated to four groups.

The study design was as follows:

 

Group

Number of

Induction phase

(6 applications - days 1 to 8)

Challenge application (day 29)

 

animals

Treatment

Irradiation

Treatment

Irradiation

Scoring

1

5

-

UV A + UV B

-

UV A or UV B

1, 4, 24, 48h

2

5

Test item

-

Testitem

-

1, 4, 24, 48h

3

10

Test item

UV A + UV B

Testitem

UV A or UV B

1, 4, 24, 48h

4

5

Vehicle

UV A + UV B

Vehicle

UV A or UV B

1, 4, 24, 48h

 

The phototoxic potential of the test item was evaluated after the first treatment and/or irradiation performed on day 1 in animals of all groups.

The photoallergenic potential of the test item was assessed as follows:

- during an induction period of 8 days, six topical applications and/or UV A+UV B irradiation (including that for phototoxic potential assessment) were performed on the anterior scapular area of animals of all groups,

- during a rest period of 20 days, the animals received no treatment and no irradiation,

- on day 29, a challenge phase was performed by topical application and/or irradiation to the posterior area of the right (UV A) and left (UV B) flanks of the animals.

For each treatment, a dose-volume of 0.1 mL of the test item at the concentration of 5% (w/w) in diethylphtalate was applied by cutaneous route. The irradiation doses of UV A and UV B were infra-erythematogenic. The cutaneous reactions were evaluated at the treatment sites. At the end of the study, animals were killed without examination of internal organs. No skin samples were taken from the challenge application sites.

 

No clinical signs and no deaths occurred during the study. The body weight gain of the treated animals was similar to that of the control animals. A questionable to moderate erythema was noted in all animals of groups 1, 2, 3 and 4 at the 1 and 4-hour readings. These cutaneous reactions decreased in intensity (questionable or discrete erythema) in almost all animals of all groups on day 2. As these cutaneous reactions were of similar intensity and incidence in animals of all groups on days 1 and 2, they could not be attributed to a phototoxic effect of the test item. In the control group 1 (irradiated only), the few cutaneous reactions observed remained within the range of a local reaction at an infra-erythematogenic irradiation dose. In the control group 2 (treated only), a discrete erythema was noted in 4/5 and 2/5 animals at the 4 and 24-hour readings, respectively. In the treated group 3 (treated and irradiated), a questionable or discrete erythema was recorded in 8/10, 9/10, 7/10 and 2/10 animals at the 1, 4, 24 and 48-hour readings, respectively. In the control group 4 (treated with the vehicle and irradiated), a questionable or discrete erythema was observed in 4/5, 4/5, 3/5 and 1/5 animals at the 1, 4, 24 and 48-hour readings, respectively. No cutaneous reactions which could be attributed to a photoallergenic effect of the test item were observed.

Under our experimental conditions, topical applications of the test item Isobornylcyclohexanol followed by UV irradiation do not induce any phototoxic or photoallergenic reactions in guinea pigs.

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