[Clinical evaluation of a topical ethyl lactate treatment of acne vulgaris (author's transl)]

Abstract

The efficacy of a lotion containing 10 p. 100 ethyl lactate was evaluated in a double-blind clinical trail during 8 weeks. Test subjects were 45 male and female patients with polymorphous juvenile acne. They were divided into three groups and received the following treatments: Group A: oral antibiotic + topical placebo lotion. Group B: oral antibiotic + topical ethyl lactate lotion. Group C: topical ethyl lactate lotion only. The lotions were applied twice daily with a swab of cotton-wool. The antibiotic doses (tetracycline hydrochloride) were decreased as the trial progressed. Patients were examined before the trial, then after 1, 2, 4, 6 and 8 weeks. At each visit, comedones, microcysts, pustules and nodules were counted on a skin surface of 9 cm2. Colour photographs were taken before and at the end of the trial and served for counting inflammatory lesions. Also, at each visit, skin lipids were sampled and analysed by I. R. spectrophotometry in order to asses the effect of the treatments on the free fatty acid/triglyceride ratio. The treatments showed similar effectiveness as regards comedones and microcysts, but only treatments A and B succeeded in reducing the number of inflamed lesions. With respect to the latter, the combined treatment B (oral antibiotic + topical ethyl lactate lotion) was more effective than treatment A (oral antibiotic + topical placebo); both treatments were more effective than treatment C (topical ethyl lactate lotion only). At the end of the trial, all three groups of patients showed significant overall improvement, but acne scores (total number of lesions) did not differ significantly between treatments. When comparing these results with literature data concerning the effects of vitamin A acid and benzoyl peroxide, it appears that ethyl lactate is slightly less effective for topical treatment of acne than vitamin A acid, but slightly more effective than benzoyl peroxide. It should be underlined that ethyl lactate is well tolerated by the skin. Analysis of sebum samples failed to yield evidence of a decrease in the free fatty acid/triglyceride ratio in skin lipids of the patients irrespective of the treatment applied.