In Vivo Human Repeated Damage Patch Test (HRIPT)

The abbreviation HRIPT stands for human repeated damage patch test. These tests, which are a clinical test method, are sometimes scientific tests performed on volunteers, that is, human subjects. For many years, the assessment of the risks to human health of skin sensitizing chemicals has been kept secret. Generally based on test results on animals. This approach, on the other hand, has inherent inaccuracies and uncertainties. Recently, a new approach has been applied and in this way uncertainties in risk assessment have been reduced. The approach is to determine the skin sensitization threshold in a human repeated damage patch test (HRIPT). In this way, an upper limit of acceptability for a single sensitizing substance is obtained in a given exposure scenario. While this approach does not normally require any human testing, where uncertainties still exist in the risk assessment, the conduct of appropriate assays, including skin permeability studies or a properly designed HRIPT, greatly contributes to the elimination of uncertainties.

Generally, in this test method, approximately 100 volunteers are each given 3 × 9-hour or 24-hour exposures over 48 weeks. After a 2-week break, both at the induction site and separately using a 24/48 hour patch a trial exposure is made in one area. Skin reactions are scored over the next few days. A number of minor technical changes were made to the protocol, including patch type, use of occlusion, duration of induction exposures, and details of the grading scheme.

The human repeated injury patch test (HRIPT) is more than 50 years old, but is still used as a confirmatory test in the safety assessment of skin sensitizers in many countries. The criticisms are mostly towards the ethical approach and the scientific validity of such tests. Therefore, there is currently no scientific justification for the many in vivo human repeated injury patch tests (HRIPTs) conducted to provide assurance regarding the risk of skin sensitization.

Our organization also provides in vivo human repeated damage patch testing (HRIPT) services with its trained and expert staff and advanced technological equipment, among the numerous test, measurement, analysis and evaluation studies it provides for businesses in various sectors.