Objective and design: In a clinical research institute the anti-inflammatory effect of pale sulfonated shale oil versus hydrocortisone was investigated in a placebo-controlled clinical trial using a double-blind design and random assignment of the treatments to the test fields.
Subjects: 20 male and female volunteers with healthy skin in the test areas participated in this trial.
Treatment: All subjects received different concentrations of pale sulfonated shale oil (2% and 4%), the active ingredient-free vehicle and a reference product containing 0.5% hydrocortisone.
Methods: Approximately 300 microl of test preparation were applied to the treatment fields. The medication was administered for 23 h. An untreated, irradiated and an untreated, non-irradiated control field were included as well. The test fields were compared intraindividually. Four different UV-doses (1; 1.25; 1.6 and 2 MED) were tested in each volunteer. The test fields were occluded for 6 h. After 7 h, measurement with a colorimeter was carried out. After measurement, the treatment was repeated. The test fields were occluded for a further 16 h and test preparations carefully wiped off. One hour later, post-irradiation color measurements were made by colorimetric detection. Variance analysis was used for statistical evaluation.
Results: 4% pale sulfonated shale oil and 0.5% hydrocortisone had a significantly greater efficacy than the vehicle (p = 0.0001). There were no differences between the efficacy of 4% pale sulfonated shale oil and 0.5% hydrocortisone (p = 0.5169).
Conclusions: These results demonstrate the anti-inflammatory efficacy of 4% pale sulfonated shale oil and help explain the clinical effects of the drug in the therapy of atopic eczema.