GD - Online B. Gabard: Corneosurfametry
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 Printversion or Abstracts 2001

Bernard Gabard
in cooperation with E. Chatelain, E. Bieli und S. Haas

Corneosurfametry: a simple method to investigate the mildness of cleansing products

Department of Biopharmacy, Spirig Pharma Ltd., CH-4622 Egerkingen, Switzerland

Irritant reactions to surfactants, cleansing products, soaps or detergents are common in clinical and occupational dermatology. The repeated use of such products may damage the skin, drying out the Stratum corneum and may cause irritant contact dermatitis. Mildness benefit has become a major claim, even overriding the primary purpose of the products, i.e. the cleansing benefit. Testing for mildness now ranks among the First concerns of the manufacturing industry. A wealth of publications deals with the clinical testing of cutaneous tolerance, trying to improve the methodology, to reduce the costs of testing and to facilitate decision-making. Differences can be assessed by clinical and/or instrumental assessment. However, this may be difficult as commercially available products are generally safe to use and none are harsh in the absolute sense. Fine ranking is difficult, if not impossible.

The mildness of 19 different syndets and shampoos, all claimed to be "mild" or "suitable for Babies", was evaluated with two methods in vivo (flex wash test, soap chamber test) and with a new one in vitro, corneosurfametry. For this purpose, the calculation of an index of irritation (IOI) was proposed. Na-laurylsulfate was used as a standard and as a model surfactant in each test. Bioengineering methods (skin colour, transepidermal water loss TEWL) were used throughout.

The results of the corneosurfametry allowed us to classify the products in three categories with increasing aggressiveness toward the horny layer according to their IOIs. None of the in vivo test was able to discriminate between the different products. However, TEWL-ranking, but not skin colour ranking from the in vivo tests showed a good correlation with I0I from the corneosurfametry.

Corneosurfametry emerged as simple, low-cost and fast new technique for ranking different materials according to their mildness. However, the skin bioengineering techniques showed that some products could lead to measurable skin reactions such as erythema. Thus, corneosurfametry should not be used alone, but should be combined with a suitable in vivo test.

Dr. Bernard Gabard

PD Dr. Christian Surber, left, in conversation with Dr. Bernard Gabard

Prof. Dr. Rolf Daniels, left, and Dr. Bernard Gabard



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