JOURNAL OF COSMETIC SCIENCE 218 placed on the skin surface of the forearm and 1 ml of PBS was pipetted onto the skin. The PBS was stirred with a glass rod for 60 s. Afterwards the extract was collected in an Eppendorf tube. STATISTICAL ANALYSIS Statistical analysis was performed using the two-tailed Student’s T-test. p-values below 0.05 were considered as signifi cant. Figure 1. Size- exclusion chromatography aluminum salt size distribution profi le of 1.2% AlCl3 solution and prototype 12% AlCl3 formulation with 0.1% taurine and 0.1% aloe extract (w/w).

TAURINE/ALOE VERA FOR BOOSTING ANTI-SKIN IRRITATION EFFECTS 219 RESULTS AND DISCUSSIONS DETERMINING THE OPTIMAL CONCENTRATION OF TAURINE AND ALOE EXTRACT Per cent AlCl3 (w/w) is the highest concentration allowed by the Food and Drug Ad- ministration in an over-the-counter product (19). Fourteen percent AlCl3 concentra- tion was selected to test for irritation because it is the highest concentration of AlCl3 we found in over-the-counter products. AlCl3 treatment alone resulted in a 5.0-fold increase in IL-1α levels compared with the untreated control. MTT assay to measure cell viability after treatment was used to normalize IL-1α data. In tissue that are co- treated with taurine or aloe extract at either 0.1% or 0.5% concentrations we ob- served drastic reductions in IL-1α levels, up to a 40% reduction (Figure 2). However, Figure 2. IL-1α concentrations in EpiDerm cell culture media (n = 3) after topical application of solutions containing AlCl3 and actives for 1 h. Negative control (NC) was untreated tissue and positive control (PC) was tissue treated with 14% AlCl3 solution without taurine or aloe extract. EpiDerm tissues were treated with 14% AlCl3 solution containing either taurine or aloe extract or both at varying concentrations to deter- mine the optimal ratio and concentration of actives.