A hydroquinone formulation with increased stability and decreased potential for irritation

Abstract

Background: Long-term treatment with a high-strength hydroquinone (HQ) cream (usually 4% HQ) is the mainstay therapy for hyperpigmentation disorders. Instability and high potential for irritancy hinders patient compliance. A new 4% HQ preparation has been designed with an innovative antioxidant for stability and a biomimetic of an herbal extract for skin calming. Aims: To investigate the activity, stability, and irritancy ofa new HQ cream. Methods: To evaluate the new HQ cream in comparison with commercial 4% HQ creams for stability by temperature stress test, for irritancy by repeated-insult patch test on human subjects, and for lightening effect using the MelanoDerm™ B skin equivalent model. Results: The new HQ is more resistant to browning and shows less irritancy than three commercially available 4% HQ products. It has comparable bleaching effect with faster onset than a 4% HQ product containing 0.05% tretinoin and 0.01% fluocinolone acetonide. Conclusion: Based on its improved stability, lower irritancy, and activity in skin lightening, the new approach to the formulation of 4% HQ may improve therapeutic outcomes by improving patient compliance to dosing. © 2007 Blackwell Publishing.