Soap Chamber

This test is used to classify a product as Mild or Harsh and to compare the relative mildness/irritancy potential of various soap/detergent type products, intended for washing the skin, whether they are liquid or solid.

The test is conducted in a panel of 20 volunteers. All test solutions would be prepared daily as 8% w/v aqueous solutions.

The test solutions are applied to the volar surface of the forearm by means of Finn chambers on Scanpor tape. Patches containing the test solutions are applied to the same sites on the arm for 5 consecutive days. Application is for 24 h on the first day (Monday) and for 6 h on the following 4 days (Tuesday - Friday).

Skin assessments are made approximately 24 h after each patch application, except the 5th application which is assessed on the following Monday. Test sites are graded for erythema, scaling and fissuring.

A daily mean average for each parameter (viz, erythema, scaling and fissures) is calculated and the values summed to give a daily total score. Soap would be characterised as mild if the total score on the final Monday of the test is less than 1, and as harsh if it exceeds 5.