A double‐blind randomized vehicle‐controlled clinical trial investigating the effect of ZnPTO dose on the scalp vs. antidandruff efficacy and antimycotic activity

Abstract

Dandruff is a common problem in approximately 30% of the world's population. Reports in the literature regarding treatment of this condition with various antidandruff shampoos usually report the level of active ingredient within the formulation. However, we propose that a more important parameter relating to antidandruff efficacy is the amount of active ingredient delivered to the scalp from the shampoo. This report describes the results from two studies designed to investigate the relationship between the level of zinc pyrithione (ZnPTO) deposited onto the scalp and the resultant scalp condition. A double-blind randomized vehicle-controlled clinical study comparing three shampoos - a vehicle, a low-depositing ZnPTO shampoo and a high-depositing ZnPTO shampoo - was carried out in the U.K. with 53 panelists with dandruff or mild-to-moderate seborrheic dermatitis of the scalp. Both shampoos containing ZnPTO were significantly superior in antidandruff efficacy to the vehicle. Furthermore, the high-depositing ZnPTO shampoo was significantly superior compared with the low-depositing ZnPTO shampoo in terms of both antidandruff efficacy and antimycotic activity. Antidandruff performance and antimycotic activity of ZnPTO-containing shampoos is highly dependent on the amount of active ingredient delivered to the scalp. Furthermore, careful manipulation of the formulation parameters of an antidandruff shampoo can result in enhanced levels of delivery of the active ingredient without having to increase the level of active ingredient within the formulation.