CHARACTERIZATION OF IRRITANT PATCH TEST REACTIONS TO TOPICAL VITAMIN-D AND ALL-TRANS-RETINOIC ACID IN COMPARISON WITH SODIUM LAURYL SULFATE- EVALUATION BY CLINICAL SCORING AND MULTIPARAMETRIC NONINVASIVE MEASURING TECHNIQUES

The study was a single-centre, double-blind randomized, placebo-contro lled within-subject comparison of 42 healthy volunteers, Occlusive pat ch test for 48 h was performed with solutions of 1 alpha,25(OH)(2)D-3 (calcitriol), two vitamin D analogues (calcipotriol and KH 1060 (lexac alcitol)), all-trans retinoic acid and sodium lauryl sulphate (SLS) as reference irritant, Solution vehicles and an empty chamber was also i ncluded, Test evaluation was performed at day 2, day 3 and again on da y 7, Test evaluation was based both on clinical scoring and on various non-invasive measuring methods. 1 alpha,25(OH)(2)D-3, calcipotriol an d KH 1060 all showed mild irritation in the concentrations tested. The number and severity of test reactions was found to be dose dependent based both on clinical scoring and on non-invasive measurements. Irrit ation of the vitamin D analogues mainly affected the vasculature with vasodilation and increased cutaneous blood flow. All-trans retinoic ac id showed irritant reactions with some similarity to the tested vitami n D analogues; however, the reactions were more prolonged. Transepider mal water loss (TEWL) was affected neither after application of vitami n D analogues nor after application of all-trans retinoic acid and it was thus concluded that these substances are non-corrosive, SLS showed the known irritant mechanism with corrosion and increase in TEWL as t he primary event.