J. Soc. Cosmet. Chem., 48, 117-121 (March/April 1997) Sebum flow dynamics and antidandruff shampoos C. PI]•RARD-FRANCHIMONT, J. E. ARRESE, and G. E. PI]•RARD, Belgian SSTC Research Center 5596, Department of Dermatopathology, CHU Sart Tilman, B-4000 Liege, Belgium. Accepted for publication June 1, 1997. Synopsis The clinical efficacy of antidandruff shampoos is correlated with both their anti-Malassezia and their squamolytic activities. The sebum flow nourishing the lipophilic yeasts is another actor on the scene, fueling the skin disorder. This study was conducted in 120 men in order to quantify the effect of eight proprietary antidandruff shampoos on sebum flow dynamics. Evaluations were made using the Lipometer ©. Two shampoos exhibited a significant effect upon the sebum follicular reservoir, steadily increasing the sebum excretion rate in time. One other product induced a significant decrease in sebum output. Present data give insight into the distinct effects of shampoos on the follicular reservoir function in androgenic alopecia. The resulting sebum flow dynamics may be significantly increased or decreased by proprietary products. INTRODUCTION Dandruff and seborrheic dermatitis are the result of excessive growth of Malassezia ova/is releasing pro-inflammatory mediators and activating an immune response (1-3). The lipophilic character of M. ovalis makes sebum a likely actor on the scene, fueling the abnormal skin condition. It has been previously shown that excessive oiliness is a disturbing side effect following regular use of selenium sulfide shampoo to control dandruff (4,5). Little is known about the variations in sebum output during other antidandruff treatments. The aim of the study was to compare the effect of proprietary shampoos on sebum flow dynamics. MATERIALS AND METHODS Eight proprietary antidandruff shampoos were used (Table I). A total of 120 men, aged 21•44 years, who suffered from androgenic alopecia of the vertex with mild dandruff, were enrolled. The study was conducted during the winter season. A three-week period of wash-out was observed during which panelists shampooed their scalps thrice weekly with a nonmedicated shampoo (mild shampoo Galenco©). At completion of this run-in period they were randomly allocated to one of eight groups receiving a test antifungal 117

118 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Table I Test Shampoos Brand name Antifungal Anatel © Piroctone olamine 1% Cystelle © Piroctone olamine 1% Dercos © Piroctone olamine 0.5% Head and Shoulders © Zinc pyrithione 1% Nizoral © Ketoconazole 2% Pevaryl © Econazole nitrate 1% Selsun © Selenium sulfide 2.5 % Zinkan © Zinc pyrithione 1% shampoo. Both the investigators and volunteers were unaware which shampoo was used. No other cosmetic product was allowed on the scalp during the three weeks prior to and during the study. The seburn output on the scalp was evaluated weekly for five weeks on the alopecic vertex using the L'Oreal Lipometer ©, equipped with a specially designed 6-ram probe (6,7). The close contact of the glass plate with the skin was rendered possible after the hair had been cut flush with the scalp surface. The amount of sebum was measured in the morning, three to four hours after shampooing. Eight successive measures at the same site were added. The sebum excretion rate (SER, lag/cm2/h) was calculated by dividing the value of the amount of sebum by the time interval between the shampoo and the measures. For each shampoo, the mean of the weekly SER values was compared to that obtained at the end of the run-in period to yield the variation in SER (V-SER) expressed in percent. Such calculation was made including data from the five-week treatment and from the last two weeks of treatment. The distribution of the numerical variable V-SER was characterized by the mean, median, and 95% confidence interval. Variations from baseline values were evaluated using the Wilcoxon test. Differences between products were tested with the Kruskal- Wallis and Dunnet tests. Regression analysis was applied to determine the V-SER changes in time. The linear, logarithmic, exponential, and power models were tested with calculation of the coefficient of correlation. All results were considered to be significant at the 5% critical level (p 0.05). RESULTS At the clinical inspection, all shampoos showed a good antidandruff activity without revealing signs of irritation. Data collected in the lipometry test are illustrated in Figure 1. Subjects using the selenium sulfide shampoo (S) showed a significant logarithmic (r = 0.70, p 0.05) SER increase in time. SER in subjects using piroctone olamine shampoos (A, D) was un- modified except for one product (C) yielding increased values from the fourth week until completion of the study. No significant change in SER was disclosed for one of the azole shampoos (P) and the zinc pyrithione-containing shampoos (H, Z). The other azole shampoo (N) induced a significant (p 0.05) SER decrease for the last two weeks of the study.