Registration Dossier

Administrative data

Endpoint:
sensitisation data (humans)
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1962-03-20
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: In accordance with sound scientific principles.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1962
Report Date:
1962

Materials and methods

Study type:
study with volunteers
Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
Human Skin Patch Test. Reactions were scored before and after patch removal for each application and were graded using the Daize scale.
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent

Method

Type of population:
general
Ethical approval:
confirmed, but no further information available
Subjects:
The technique involved the use of 101 volunteer subjects, age range 19 to 62.
Clinical history:
no information
Route of administration:
dermal
Details on study design:
Reactions were scored before and after patch removal for each application and were graded using the Daize scale. The undiluted test compounds (MRD-61-20, MRD-61-21, MRD-61-22, MRD-61-23, and MRD-61-47) as received were evaluated under simulated use conditions, preceded and followed by patch testing. The technique (Traub, et al., AMA Arch. Dermatol. & Syphilol. 69, 399, 1954) involved the use of 101 volunteer subjects, age range 19 to 62.

The patch tests were first carried out using a pilot group of ten males to perfect the method of application. From this evolved the form of patch that was used for the remainder of the subjects. This consisted of five filter paper discs, 3/8 inch in diameter, suspended by thread between two rows of twill tape. The discs were about 3/4 inch apart and equidistant from the tape. The patch was held in place on the arm by a bracelet arrangement consisting of a short piece of elastic bandage sewn to the ends of the patch. The use of a patch of this type prevented weeping of the test materials into each other, and also prevented contamination of the materials by adhesive tape. A patch containing five discs was applied to each arm. Each disc was saturated with 0.06 ml of the test materials (MRD-61-20, MRD-61-21, MRD-61-22, MRD-61-23, and MRD-61-47); less would not dampen the skin and a greater amount would spread to other patch sites. The initial and challenge patches were left in contact with the skin for a period of four to six hours, after which the patches were removed and the skin sites evaluated for signs of irritation. The skin sites were re-examined after 24 hours and, in some subjects, after 48 hours.

Following the initial patch the test materials were applied by cotton applicators to the subjects' forearms once or twice daily, five days a week, for three weeks. Application of each test material was made on a prescribed area and special care was maintained to prevent one material from running into another or contaminating another site. The materials were allowed to air dry and the subjects returned after approximately four hours for the second daily application. The application sites were examined twice a day, just before the first application, and again just before the second application of the test materials. After the final daily application the subjects were given a rest period of 10 to 14 days and then received a challenge patch in the sane manner described above for the initial patch. The challenge patches were applied to approximately the same skin sites that were used with the initial patches. Some subjects were also given a second challenge patch.

A record was kept of the skin responses observed at the tine of examination and the reactions scored as follows:
0= a no visible reaction
+/- = slight erythema
+ = definite erythema
++ = erythema and edema
+++ = erythema, edema, with vesicles

Responses to initial and challenge patches were evaluated statistically by calculating for each compound an index of reaction, or response score, using the following formula:

Response Score = [(N0)(0) + (N1)(l) + (N2)(2) + (N3)(3)+ (N4)(4) (100)] / [(4)(total N)]

where

N = number of subjects tested;
N0 = number of subjects with response 0;
N1 = number of subjects with response +/-;
N2 = number of subjects with response +;
N3 = number of subjects with response ++;
N4 = number of subjects with response +++

Maximum possible score =100 (the case if all subjects show +++ reaction).

Scores for each patch were interpreted according to the following key:
0-12 generally non-irritant;
13-37 slightly irritating;
38-62 moderately irritating;
63-87 highly irritating;
88-100 extremely irritating

Results and discussion

Results of examinations:
Initially, investigations were carried out to determine a suitable means for patch testing MRD-61-20, MRD-61-21, MRD-61-22, MRD-61-23, and MRD-61-47. The preliminary investigations revealed that none of the materials could be patch tested using a closed patch without producing severe primary irritation to the skin at the patch test site. The irritation produced by the test materials was due to the closed patch and the degree of irritation was associated with tightness or pressure of the patch on the skin, which trapped the vapors and prevented or slowed down evaporation. There evolved various modified patches designed to eliminate pressure as much as possible, to permit free evaporation and to avoid trapping the vapors between the patch material and the skin. The selected patch from the preliminary investigation appeared satisfactory, in that primary irritation observed was minimal. The patch allowed the test materials to be in intimate contact with the skin and evaporation could occur. Tightness of the patch, which influenced pressure, was not entirely eliminated by the patch that was used. Subjects on flexing or extending their arms, or holding their arm close to the body, contributed to the pressure, and this was impossible to prevent.

The total number of applications for all subjects was 2895 (193 daily applications of each material for 15 days. Twice daily to 92 subjects; once daily to 9 subjects). The results were: MRD-61-20: 65 subjects scored a 0; 13 subjects scored a +/-; 19 subjects scored a +; 4 subjects scored a ++. MRD-61-21: 58 subjects scored a 0; 21 subjects scored a +/-; 21 subjects scored a +; 1 subjects scored a ++. MRD-61-22: 78 subjects scored a 0; 11 subjects scored a +/-; 11 subjects scored a +; 1 subjects scored a ++. MRD-61-23: 87 subjects scored a 0; 7 subjects scored a +/-; 7 subjects scored a +; 0 subjects scored a ++. MRD-61-47: 74 subjects scored a 0; 16 subjects scored a +/-; 10 subjects scored a +; 1 subjects scored a ++.

The following data presents the reaction scores from the initial and challenge patches, as compared by the Chi-square test. A compound is assumed to have sensitizing potential if the response scoring is significantly increased by the challenge patch. The difference between the initial response and the challenge response scores were compared by the Chi-square test of significance at the 5% probability level.

The results of the challenge patch were: MRD-61-20: 70 subjects scored a 0; 9 subjects scored a +/-; 20 subjects scored a +; 2 subjects scored a ++. MRD-61-21: 65 subjects scored a 0; 15 subjects scored a +/-; 20 subjects scored a +; 1 subjects scored a ++. MRD-61-22: 66 subjects scored a 0; 19 subjects scored a +/-; 15 subjects scored a +; 1 subjects scored a ++. MRD-61-23: 68 subjects scored a 0; 21 subjects scored a +/-; 12 subjects scored a +; 0 subjects scored a ++. MRD-61-47: 73 subjects scored a 0; 23 subjects scored a +/-; 5 subjects scored a +; 0 subjects scored a ++.

There were 2,895 uncovered applications to the skin during the three-week open patch period, with each test material, without any evidence of skin reaction to any of the materials. Usually observed from each daily application was the appearance of a dehydrating effect on the skin at the application site similar to that produced by solvents such as alcohol or ether following skin exposure and evaporation.

The challenge patches with the materials were made to approximately the same skin sites as those in the initial patch. A number of subjects again showed skin responses from the challenge patch. The responses were similar to those found in the initial patches. A number of subjects were given a second challenge or rechallenge patch at a skin site very near the reactive skin site. In no subject did the rechallenge patches cause flare-up by the first challenge patch. From the nature of the responses produced by the first challenge patch on all subjects and by the second challenge patch on some subjects, there was no evidence that skin sensitization was produced. Statistical analysis, by means of the Chi-square test, indicates that there are no significant increases in the responses by the challenge patches over the initial patches.

Applicant's summary and conclusion

Conclusions:
MRD-61-20, MRD-61-21, MRD-61-22, MRD-61-23, and MRD-61-47 did not cause primary skin irritation under semi-occlusive conditions and were not skin sensitizers.
Executive summary:

MRD-61-20, MRD-61-21, MRD-61-22, MRD-61-23, and MRD-61-47 were evaluated for skin irritating properties in humans following a simulated use patch technique. A total of 101 subjects, including males and females, participated in the program. Each subject was patch tested before and after a three-week simulated use period. Under conditions and procedures used in the investigation MRD-61-20, MRD-61-21, MRD-61-22, MRD-61-23, and MRD-61-47 will not be considered primary skin irritants under semi-occluded conditions. None of the test materials produced skin fatigue on repeated daily application during a three-week simulated use period. None of the test materials were skin sensitizers.