HRIPT (Human Repeat Insult Patch Test) using 48 hours repeated occlusive patch is the standard procedure used to diagnose contact allergy resulting from type IV hypersensitivity. This test is based on the principle that an allergic individual would elicit a systemic response with an allergen. Therefore, if the substance is applied to the skin on any part of the body it will result in dermatitis at the site. The patch test is performed by applying allergens (test materials in this case) under occlusion on the skin under standardized conditions with repeated dosing for three weeks and thereafter upon complete resolution of the reaction the test article/ allergen is challenged at the test and naïve site.

There are 5 test materials which are components of a medical device. 0.25 ml of extractants in sterile saline and sterile sesame oil and controls will be loaded in an adhesive bandage with 18mm Finn chambers affixed. 

There will be 4 phases: Induction phase, rest period, challenge phase and rechallenge phase. This phase of the study will be conducted over approximately 3.5 weeks and will include 10 multiple, 48 hours (72 hours on weekends)  sets of patches at a single site on the upper back. Each patch will be left on for 48hours (window period: +1hour) and then removed by the investigator/designee at the study site. Post patch removal, test sites will be wiped with water and a trained assessor will grade the skin site for skin reactions. The next set of patches will be applied on the same site immediately after skin site assessments are performed. The 10 sets of patches will be numbered P1, P2, P3, P4, P5, P6, P7, P8, P9, and P10.

The rest phase will last approximately 21 days. The challenge phase consists of similar patching procedure for 48 hours of patches 11 and 12. On visit 17, assessment 96 hours post patch removal will be done. Reachallenge phase will be performed in case of ambiguity where patches will be applied and scored 48 hours and 96 hours after patch application.