Recommendations for a Cumulative Skin Irritation Study

Dermatologic disease that might interfere with the evaluation of test site reaction should be grounds for exclusion. 

The study should be a randomized, controlled, repeat patch test study that compares the test patch with the innovator patch. Placebo patches (transdermal patch without active drug substance) or high- and low-irritancy controls (e.g., sodium lauryl sulfate 0.1% and 0.9% saline) can be included as additional test arms. 

Each subject applies one of each of the patches to be tested. Test sites should be randomized among patients. Patches should be applied for 23 hours ( 1 hour) daily for 21 days to the same skin site. At each patch removal, the site should be evaluated for reaction and the patch reapplied. 

Application of a test patch should be discontinued at a site if predefined serious reactions occur at the site of repeated applications. Application at a different site may subsequently be initiated. 

Scoring of skin reactions and patch adherence should be performed by a trained and blinded observer at each patch removal, using an appropriate scale. 

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