Correlating sensory effects with irritation.
The goal of this preliminary study was to examine data collected in the course of the development and conduct of the behind-the-knee (BTK) test for correlations between the objective scores of erythema and the sensory effects reported by the panelists. In addition, the intensity of physical characteristics of femcare products and prototypes was evaluated using the descriptive analysis panel (DAP) and results were compared to the BTK results to determine if certain physical characteristics of the products correlated to different sensations experienced by the BTK panelists. Test materials were commercially available or developmental catemenial products. In the BTK test, samples were applied daily to the area behind the knee and held in place for 6 hours per day for 5 consecutive days by an elastic knee band of the appropriate size. Irritation was graded 30-60 minutes after removal of each application. The DAP uses individuals trained to recognize and grade certain physical characteristics of products, including degree of plastic feel, scratchiness, glide, and cottony feel. In the BTK studies, the ability to differentiate between the test samples via reported sensory effects correlated with the ability to differentiate via objective scores for irritation in seven of 15 comparisons. A correlation between the magnitude of the irritation score, independent of the specific test sample, and reports of adverse sensory effects was observed in 13 of 15 comparisons. Two comparisons conducted in the BTK were also evaluated using the DAP. For one comparison, there was a clear difference in the product physical characteristics in the DAP that was consistent with mean erythema scores and reported sensory effects in the BTK. For the other comparison, there was no clear difference between the two products by either the DAP or the BTK.