ABSTRACT
BACKGROUND: There are some variables including chamber size in irritant patch test responses. Several non-invasive bidengineering methods for quantifying and obtaining information have been developed in recent decades. OBJECTIVE: Our study was done to compare the effect of chamber size and the volume effect on the irritation potential of 1% SLS solution. METHODS: Patches with 1% sodium lauryl sulfate(SLS) solution were applied to the volar forearm of 14 healthy volunteers for 24 h. Finn chambers with 8mm(20ul), 12mm(60pl), 18mm(80ul, 200ul) inner diameters were used. Visual score and transepidermal water loss (TEWL) were measured at 30 min after removal of the patches, and every 24 h up to 4 days. RESULTS: The results are summarized as follows. 1. Visual scores were 0.18+0.32(8mm), 0.75+0.33(12mm) and 0.64+0.41(18mm) at 24 h after removal of 1% SLS and were 0.11+0.29, 0.50+0.34 and 0.25+0.26 on 4 days after removal. They were inereased 30 min and 24 h after removal and decreased towards normal 4 days after removal. By chamber size, the skin response with the large Finn chamber(12mm) increased more significantly than with the small Finn chamber(8mm). However, there were no significant differences in skin response between large and extralarge Finn chambers(18mm). 2. TEWL values were 11.86+4.09, 23.05+6.1l and 22.24+7.54g/m/h at 30 min after removal and were 9.37+2.30, 1..49+3.08 and 14.56+5.00g/m/h on 4 days after removal. They were increased 30 min after removal and decreased towards normal 4 days after removal. By chamber size, their results were the same as visual scores. 3. By visual score and TEWL, the skin response with 200pl of 1% SLS increased more significantly than 80pl in the extralarge Finn chamber. CONCLUSION: The small Finn chamber may be too small to elicit sufficient cutaneous irritation for evaluation. The large Finn chamber having larger test areas may be suitable to yield positive reactions to certain irritants. Also, the quantity of test solution per mm skin may be of importance for the skin response.