Rectal mucosal irritation test. ISO-10993-23: 2021 - Biological evaluation of medical devices - Irritation Tests.

Test with the Certificate of Good Laboratory Practices (GLPs).

This test is designed to evaluate materials/substances that are going to be in contact with the rectal mucosa and its safety cannot be determined by other methods. Materials or substances that have been shown to cause skin or eye irritation, or have a pH ≤ 2.0 or ≥ 11.5 should not be tested.

The test is performed on six female rabbits (three for the test group and three for the control group), which are free of signs of rectal inflammation, rectal exudate, or other signs of rectal infection. If there were equivocal results with this number of rabbits, the test should be done with more animals. The animals are exposed to the test sample rectally every 24 hours, for five consecutive days, and are evaluated every 24 hours to detect the presence of exudate, erythema or edema.

The complete evaluation of the effect is made after the humanized sacrifice, and the necropsy to observe the macroscopic findings behind the rectal opening to detect signs of irritation, mucosal damage or necrosis. In addition, a histopathological study should be performed to detect signs of microscopic inflammation in three different regions of the vagina exposed to the test sample in each of the three animals (9 histopathological tests).