Oral mucosa Irritation test. EN ISO-10993-23: 2021 -  Biological Evaluation of Medical Devices. Irritation Tests.

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

This test should only be considered for products aimed at contact with oral tissues and whose safety data cannot be obtained by other methods. The test evaluates the potential of the product under test to cause irritation of the oral tissues. Products known to be skin or eye irritants that have a pH ≤ 2.0 or ≥11.5 should be excluded from the test, in which case these products should be labeled as potential irritants for oral tissues. When in spite of this, the test must performed, it must be justified and documented.

This test is carried out with the product in at least 3 Syrian adult hamsters and other animals must be included as negative controls, excluding those animals that show anomalies in the cheek pouches. If equivocal results are obtained, the number of animals must be increased.

The product subjected to the test can be of solid nature (pieces of maximum size of 5 mm), liquid (products of this nature or extracts of solid products of larger size of 5 mm). The solid products are put in direct contact with the cheek pouches; Liquid products or solid product extracts should be placed in cotton or placed directly in the pouches. Only one of the pouches is used and the other contralateral pouche is used as a control. The duration of the exposure depends on the use of the product, but it must not be less than 5 minutes. For acute exposures the exposure should be repeated every hour for 4 hours and for repeated exposures the duration, interval between exposures and number of applications should be considered according to the intended clinical use of the product under test.

The evaluation of the response must be performed macroscopically and microscopically by histopathological examination of the sacrified animals. With the macroscopic and microscopic findings a numerical index of irritation is obtained that allows cataloging the product as non-irritant, minimal irritant, mild, moderate or intense.