26 TESTING Figure 2: Measurement of skin properties in the lab.
pigmentation plays a role in many claims and erythema measurements are basic measurements in regards to product safety and tolerance.
l Skin elasticity and measurement of wrinkles and lines are typical basic anti- aging claim supporters.
l The skin pH level is an important dermatological parameter that in testing will show the impact of the product on the skin. The pH measurement is especially important when developing cleansing products or shampoos. Then, depending on the nature of the
product, other methods can be useful, e.g. fluorescent-based cameras to monitor the acne bacteria development, systems to analyze dandruff and many, many more. More and more tests are performed on artificial skin, skin equivalents or cell cultures. Those tests are economical (no ethics commission, no volunteers) and a perfect screening base for many safety and efficacy tests. Since disruption of the skin barrier will point to a sensitizing effect, especially the TEWL measurement is often used in pre-screening for product safety and tolerance. Meanwhile, for the commercially available cultured skin sets, measurement methods have been developed, e.g. TEWL measurement on up to 24 cultured skin wells at the same time. Measurement methods can also serve to generate ideas and new claims around a product which may not have been obvious when starting the development of the product. A new, very unique system to assess mechanical parameters of the nail (e.g. nail hardness, elasticity, structural strength) for example, can help to develop innovative claims around hand- and nail care. Not many researchers were able to
PERSONAL CARE NORTH AMERICA
study those parameters in the past. Devices that allow assessment of multiple different parameters at the same time are particularly economic and multi- talented. An example: Visioscan®
oil restoring, nourishing, rich, balancing, normalizing, pore refining/pore activity decreasing… There are virtually no limits. The use of skin measurement equipment in most cases is easy to learn. You need not be an expert to use such devices. However, skin is not an inanimate fabric like the cloth of a jacket or a trouser. It is a living organ, in constant exchange with the inside of the body and the environment. Therefore, a detailed protocol should be worked out that includes the selection of the suitable measuring methods, ideal testing subjects and skin sites, preparation of the skin before measurement, testing type, maintenance of standard ambient conditions, performance of the measurements, product application procedures and many more. For good comparison of the measurements, try to standardize as many factors as possible. Numerous product studies have been published and can serve as a landmark for your own study design. There are also publications on general advice for skin testing that can assist in establishing your testing protocol.1, 2
– a special
camera based on UV light to show detailed non-glossy, close-up images of the skin surface. On these images topographic parameters such as smoothness, roughness, wrinkles, texture and anisotropy can be calculated. At the same time, the camera can be used with special foils to analyze the sebum spreading in real time and the desquamation level of the skin. Spots, pores, scalp and nails can be monitored. When used after shaving, hair growth, thickness and number can be studied. With this kind of equipment, many different parameters and body sites can be analyzed in little time. Supported claims could be (among many others): anti-wrinkle, anti- aging, smoothing, rejuvenating, anti- roughness, hydrating, against dry/scaly skin, exfoliating, clean shaving, against oily skin, anti-dandruff, anti-acne,
cleaning/purifying, against imperfections,
What to consider Before going ahead with your trials using measuring equipment, there are some crucial points to be considered: You need to select relevant
measurements to substantiate the intended claim. Many devices offer modular functions, enabling you to combine different measuring probes according to your requirements to one basic station and work with all probes at the same time. Also consider that you might like to compare your testing results to results that have already been published on other products. To be sure that you have this possibility, you should pick standard devices that have already been used in similar studies or are covered by specific guidelines, such as the new revised EEMCO guidance for the in vivo measurement of water in the skin.3 Please also heed the manufacturer’s specifications on regular calibration of the equipment.
Consider the necessity of randomization, blind and double-blind studies. Especially in the days of increased data privacy, you also have to ensure that the subject data cannot be externally accessed.
Figure 3: Monitoring the activity of the acne bacteria.
Environment You also need to furnish a dedicated room for the testing as well as a waiting area close-by for acclimatization and preparation of the subjects. The testing room should be quiet and intimate with no disturbances from people passing by or from machinery causing noise or air turbulences. Ambient temperature and humidity will have an impact on the results. Ideally, you would
March 2020
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72
