Studies on Skin Irritancy of Topical Agents �Third Report

Skin irritancy of topical agents was studied with 48 hours closed patch test. The following resuts were obtained : 1) In order to compare the skin irritancy between the products or the product and its vehicle, it was considered to be appropriate to test the same materials with the same subjects, or to evaluate with skin irritancy index and skin reaction pattern if the subjects were different. 2) We propose the standards which evaluate the skin irritancy of topical agents which are divided into two major groups, that is, steroidal topical agents and the others. 3) The result studying the irritancy of the steroidal topical agents and their vehicles suggested that irritant reaction might occur if the concentraion of propylene glycol in the vehicle was more than 10%. Since there was no difference in the intensity of skin irritancy between nonsteroidal topical agents and their vehicles, it was clarified that the skin irritancy of the vehicles must be kept low in order to make good nonsteroidal topical agents that show safety in the point of skin irritancy.