Sex-related differences in response to zinc pyrithione shampoo vs. non-anti-dandruff shampoo.

OBJECTIVE: Sex-related differences in skin properties may be expected to impact dandruff formation and treatment. A meta-analysis approach was undertaken to investigate potential differences between males and females in response to zinc pyrithione (ZnPT) treatment vs. non-anti-dandruff (AD) shampoo. A separate pooled statistical analysis of ceramide and total protein loss endpoints was also undertaken to assess potential sex-related differences in stratum corneum properties that might influence response to ZnPT vs. non-AD shampoo in subjects with dandruff. METHODS: The meta-analysis approach included data from 17 half-head, double-blind, randomized studies (N = 2088) undertaken in Asia to assess the effectiveness of 1% ZnPT shampoo and/or non-AD shampoo in reducing dandruff severity, as assessed by Total Weighted Head Score Adherent Flake (TWHS-AF) methodology. Treatment duration was 4 weeks, with TWHS-AF measured at weekly intervals. Data from an additional three studies (N = 143) conducted in Asia were included in the pooled analysis of ceramide levels and protein loss from scalp skin of subjects with dandruff. RESULTS: Response to 1% ZnPT vs. non-AD shampoo was greater in males than in females at all time points; after 4 weeks, the between-treatment difference in TWHS-AF was -17.5 (95% confidence interval [CI] -19.5, -15.5) in males and -11.1 (-13.2, -8.9) in females. Sex-related differences were observed between males and females in response to both 1% ZnPT and non-AD shampoos. Males had a stronger response than females to treatment with 1% ZnPT shampoo, while dandruff decreased to a greater extent in females than in males when using non-AD shampoo. Statistically significant sex-related differences in ceramide levels and total protein loss were observed (both P < 0.01). Ceramide levels were 0.76 times lower (95% CI 0.60, 0.97) in males than in females, while total protein loss was 1.4 times greater (95% CI 1.1, 1.9) in males than in females. CONCLUSION: Males show a greater response than females to 1% ZnPT shampoo, while females show a greater response than males to non-AD shampoo. These findings may in part be explained by the sex-related differences observed in stratum corneum properties, which may make males more prone to dandruff than females.

Understanding the dandruff scalp before and after treatment: an in vivo Raman spectroscopic study.

OBJECTIVES: To study and characterize the stratum corneum (SC) of dandruff scalp using in vivo Raman spectroscopy, to study how it compares with the non-dandruff scalp and to see the effect of treatment with a zinc pyrithione (ZnPTO)-based anti-dandruff shampoo. METHODS: The scalp skin was measured using a recently developed in vivo Raman probe. This method allows the inherent molecular components of the SC to be measured in vivo and confocally with depth, in particular the levels of natural moisturizing factors (NMF), lipids, lactic acid, urea and water. RESULTS: Depth-profile data for the skin components in dandruff SC in vivo are shown for the first time. The dandruff SC has lower NMF than the non-dandruff SC (0.16 compared with 0.39 a.u.), lower hydration, elevated levels of urea and lower levels of lactic acid. Treatment with an anti-dandruff shampoo containing 1% ZnPTO substantially restores the levels of each of these components close to the non-dandruff levels. Further to this, it is shown that sebum penetrates deeper into dandruff SC and at higher levels compared with non-dandruff SC. The levels of sebum localized within the SC are also brought closer to those of the non-dandruff condition after ZnPTO treatment. CONCLUSION: The in vivo Raman probe has allowed the direct measurement of dandruff-affected skin in situ for the first time. It has been shown that the dandruff SC is different from that of the non-dandruff scalp and that it is changed by treatment with shampoo containing ZnPTO and brought towards the characteristics of non-dandruff scalp. It offers novel insights into how the nature of a healthy scalp should be defined.

Enhanced efficacy and sensory properties of an anti-dandruff shampoo containing zinc pyrithione and climbazole.

Dandruff is a common complaint and is suffered by as much as half of the population at some time post puberty. The condition is characterized by the presence of flakes on the scalp and in the hair, and is often accompanied by itch. The most common treatment for dandruff is the use of shampoo formulations that contain fungistatic agents such as zinc pyrithione (ZPT) and octopirox. Whilst most antidandruff shampoos are effective in resolving the symptoms of dandruff these shampoos can often result in hair condition that is less than acceptable to consumers which can lead to a tendency for them to revert to use of a non-antidandruff shampoo. This can result in a rapid return of dandruff symptoms. The aim of this investigation was to study the impact of using a combination of antidandruff actives and silicones on the resolution of dandruff and to deliver superior sensory properties to the hair. We have demonstrated that shampoo containing the dual active system of ZPT/Climbazole deposits both active agents onto a model skin surface (VitroSkin) and reduces Malassezia furfur regrowth in vitro. Clinical evaluation of the dual active shampoo demonstrated superior efficacy and retained superiority during a regression phase where all subjects reverted to using a non-antidandruff shampoo. We have also demonstrated that it is possible to deposit silicone materials from antidandruff shampoo uniformly over both virgin and damaged hair fibres that results in smoother hair fibres (as evidenced by reduced dry friction). This combination of antidandruff agents and conditioning silicones delivered from a shampoo provides subjects with superior antidandruff efficacy and desired end sensory benefits ensuring compliance and longer term dandruff removal.