According to the results and findings generated in this qualification study, we have a reliable tool now that enables us to test cosmetic products for hair treatment in a highly automated way with a sufficient degree of precision and accuracy to detect even small changes in hair diameter during cosmetic trials.

The purpose of our studies was to verify efficacy and skin compatibility of a medical face care system containing 2% lactic acid (LA) as active ingredient in a specially designed vehicle (Follicle Targeting System) in adult subjects with mild acne vulgaris. The first study (46 patients) demonstrated superiority of 2% LA in comparison to 2% salicylic acid with respect to number of comedones and inflammatory lesions. The second study evaluated 90 patients receiving distinct combinations of face care products (Eucerin) Impure Skin, Hamburg, Germany), i.e. cleansing gel, facial tonic (2% LA) and cream gel (2% LA). All treatments were performed twice daily over a 12 weeks period. Lesion counts, cyanoacrylate biopsies and determination of quality of life by questionnaires were performed at different timepoints. A reduction of comedones by 56% corresponding to an 46% increase of quality of life index was demonstrated in patients applying cleansing gel, facial tonic and cream gel. For the first time we were able to show a significant improvement concerning the quality of life after using a new face care line. Especially adults with mild forms of acne may benefit from this effective skin care regimen.

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A time- and cost-effective sweat casting method using the forearm as test site to assess the efficacy of several anti-perspirant formulations with a low number of test subjects has been evaluated and qualified. The imprint sweat casting method is based on a 2-component silcone-imprint technique to measure the efficacy of more than eight products in parallel with the same test subject. In studies using aluminum chlorohydrate (ACH) formulations as test anti-perspirants, a clear-cut correlation could be demonstrated between sweat gland activities measured by the imprint method and gravimetric measurement of sweat gland activities. Concentration-dependent inhibition of sweat gland activity could be observed with the imprint technique up to an ACH concentration of 15%, and all formulations containing 2% ACH or above resulted in statistically significant reduction of sweat gland activity (P < 0.001) when compared with untreated control areas. Furthermore, the SDs of individual studies using the imprint technique were in a range of +/-20% of sweat gland activity, which can be regarded rather low for in vivo measurements of a complex process like sweat secretion. A group-wise comparison between the measurements of anti-perspirant activity as determined by the imprint protocol and the Food and Drug Administration (FDA) Guideline compliant gravimetric hot-room protocol revealed that the test results for anti-perspirant activity obtained with the imprint protocol are similar to those obtained with the hot-room protocol. Moreover, the data generated with the imprint protocol have a high predictive value for the outcome of a later guideline-compliant hot-room test. As the imprint casting method tends to be a little more sensitive for formulations with low anti-perspirant activity, and seems to be associated with less interassay variability than the standard gravimetric hot-room test, the imprint casting method may select products which later fail to pass the standard gravimetric hot-room test. Meanwhile the imprint sweat casting has proven to be a robust method useful to support efficacy-oriented product development. Therefore, in later stages of utilization it might even evolve into an efficient claim substantiation tool.

Propionibacteria are gram-positive anaerobic bacteria which inhabit the deeper parts of sebaceous follicles, normally low in oxygen. They produce porphyrins which are probably partially dispersed into the surrounding medium composed of sebaceous lipids and desquamating cells from the follicular wall [1]. Porphyrins are strongly fluorescent; their excitation maximum is located around 400 nm, emission bands are mainly in the range between 600 and 700 nm [2]. Illumination of the skin with light of the appropriate wavelength allows visualization of fluorescent glands within facial areas and the upper back [3] (Fig. 1). Assuming that fluorescence intensity and porphyrin content are related, which has been proven in the case of uptake of porphyrins by propionibacteria in culture [4], and knowing that fluorescence intensity is strongly related to the population density of at P. acnes the skin surface [5] and that comedones are densely populated with propionibacteria [6] , fluorescence intensity of individual glands could be a marker for comedonal content and for the comedogenic potential of