THE GREASINESS OF MOISTURIZERS 177 VOLUME APPLIED The applications studied were 25 121/25 cm 2, 50 121/25 cm 2, 100 121/25 cm 2, and 150 121/25 cm •. The volume was carefully spread with a rubber-gloved finger. The finger covers were weighed after application to ensure that a no major differences occurred due to the moisturizer adherent to the cover. Blotting was done after 20 minutes with the blotting paper (25 cm •) pressed against the skin with a rubber-gloved hand for two minutes (n = 15). TIME ALLOWED FOR ABSORPTION A previous study has suggested that the water phase evaporates within 15 minutes of a single application of a moisturizer (1). A standard amount of moisturizer (50 121/25 cm 2) was applied, and blotting was done after 20, 40, 60, 120, and 180 minutes. Blotting was done using standard-sized blotting paper (25 cm 2) and an even, firm pressure from a rubber gloved-hand for two minutes (n = 10). TIME ALLOWED FOR BLOTTING A standard amount of moisturizer (50 121/25 cm 2) was applied, and blotting was done after 20 minutes. Blotting was done using standard-sized blotting paper (25 cm 2) and a rubber-gloved hand for 30, 45, 60, 90, or 120 seconds (n = 15). AREA STUDIED The same density of moisturizer was applied in areas of different size (50 121/25 cm 2 and 200 121/100 cm2), and blotting was done after 20 minutes. Blotting was done using standard-sized blotting paper (25 cm 2) and a rubber-gloved hand for 120 seconds (n = 15). REGION STUDIED Dry skin (volar forearm) and sebaceous skin (upper back) were compared. Moisturizer was applied in different areas (50 121/25 cm2), and blotting was done after 20 minutes. Blotting was done using standard-sized blotting paper (25 cm 2) and a rubber-gloved hand for 120 seconds (n = 15). BLOTTING PRESSURE Moisturizer was applied (50 121/25 cm2), and blotting was done after 20 minutes. Blotting was done for 120 seconds either with a rubber-gloved hand or with a 1-kg weight (n = 15). TYPE OF BLOTTING PAPER The blotting capacity of filter paper with different mean pore sizes from 0.4 to 5.0 12m was compared (standard, small, medium, big filter type BB, OOH, OOK and OOR, Munktell, Sweden). Moisturizer was applied (50 121/25 cm2), and blotting was done after 20 minutes. Blotting was done for 120 seconds with a rubber-gloved hand (n = 15).

178 JOURNAL OF COSMETIC SCIENCE Optic methods have previously been used to study skin surface lipids. Using the pro- posed amount of moisturizer, direct optical measurement of skin surface lipids was impossible, as the results were beyond the range of the apparatus. Skin surface lipids were therefore measured using the Sebumeter © (Khazaka & Courage, Cologne, Germany) after blotting. Blotting is not an absolute process and is modified not only by the method used in the actual blotting, but also by the dynamic absorption of the lipids into the superficial compartment of the skin. Using the Sebumeter for further measurement of skin surface lipids after blotting may therefore add validity to the proposed method by analogy with previously described technology. Weighing was done using a Sartorius Basic scale (0.001-100 g) (Sartorius, G6ttingen, Germany). Using this method, the greasiness of five commonly used creams on the Danish market was studied and compared to that of a protective cream, a gel, and an untreated control area. Each measurement was performed in triplicate and the mean value used in further calculations. Descriptive statistics as well as non-parametric statistics (Spearman rank correlation and Kruskall-Wallis paired comparisons) were used. RESULTS Methodological variation was described by the coefficient of variance (--SD*100/mean), which was found to be in the range of 8%-44% (see Table II). A large coefficient of variation was seen when small amounts of cream were present, e.g., if only a little had been applied or if the time given for absorption was long. A standard procedure was chosen by selecting a setup that was practical to manage and in which all elements had a low coefficient of variance. The standard procedure was: application of 50 pl/25 cm 2 moisturizer on volar forearm skin. After 20 minutes blotting was done with a 25 cm 2 (5 by 5 cm) piece of ordinary filter paper with pores of medium size. Blotting was done for 120 seconds with firm pressure applied by a rubber-gloved hand. The final chosen standard procedure had a coefficient of 23%. The amount of excess residual cream following a single application of the different moisturizers, protective cream, and gel is shown in Table I. Vaseline © left the highest proportion of the applied cream as residue, while the gel tested left only little residue, which was in good accordance with the clinical impression of their greasiness. Because absorption into the skin is a relative rather than absolute step, complete reabsorption by blotting is not possible in any process resembling actual use. The overall correlation between blotted moisturizer and unblotted residual skin lipids as measured by the Sebumeter is shown in Figure 1, which shows a significant positive correlation between the two methods (p 0.0001, Spearman rank correlation). DISCUSSION Our observations suggest that simple blotting under standardized conditions is a reliable method for quantification of non-absorbed excess moisturizer. The methodological varia- tion as assessed by the coefficient of variance is within the same range as many recognised biophysical measurements of the skin, and this simple method may therefore be of use in future studies of moisturizer greasiness and efficacy.