Formulation of chitosan patch incorporating heartwood extract for improving hyperpigmentation.

heartwood extract contains the bioactive compound artocarpin which exhibits melanogenesis inhibitory activity. However, the extract has poor solubility which affects the skin permeability of the compound. A chitosan hydrogel patch incorporating heartwood extract was formulated to enhance the delivery of an amount of artocarpin sufficient for depigmenting the skin. The extract was prepared as an o/w microemulsion before blending with an aqueous solution of chitosan. The hydrogel patch was formulated by blending in a 1:1 ratio by weight of 4% w/w chitosan solution and 0.04% w/w extract microemulsion which provides optimal values of the mechanical properties of the patch. The release of artocarpin from the formulated patch (artocarpin content, 0.07 mg/cm) exhibited two phases; the rapid rate (0-15 min) averaged 0.73 µg/min/mm, and the slow rate (15-240 min) averaged 0.02 µg/min/mm. The formulated patches significantly improved the hyperpigmented area of the subjects after 3 weeks of application. No adverse events were observed. The results indicate that the formulated chitosan hydrogel patch delivers an effective amount of incorporated artocarpin depigmenting action.