Abstract
Hyperpigmentation is a hypermelanosis occurring in all skin types and results from the overproduction of melanin or an irregular dispersion of pigment after cutaneous inflammation. Patients with hyperpigmentation can have a significant psychosocial impact on skin-of-color patients, including Asian. There are a variety of medications and procedures added to photoprotection cream that can safely and effectively treat hyperpigmentation. A fixed triple combination cream, containing 4% Hydroquinone (HQ), 0.05% Tretinoin (Vit. A acid), and 0.01% fluocinolone acetonide (steroids), called Tri-Luma from Galderma Laboratories (Fort Worth, TX), offer maximal efficacy for clinical trial. HQ and Vit. A Acid can inhibit the formation of melanin by inhibiting the tyrosinase in melanocytes in the bottom of epidermis layer. Fluocinolone acetone, the steroids can eliminate the irritation caused by hydroquinone or tretinoin. However, clinical study showed that over 87.5% of patients were noted to have side-effects with cream treatment because of the Hydroquinone cytotoxicity and slow degradation. In this study, we proposed a new design of microneedles patch with different height for different skin layer to treat hyperpigmentation. For the deeper melanocyte in the bottom of epidermis layer, longer microneedle in the center of patch served as a fast released carrier loaded active ingredient HQ and Vit. A Acid for drug localization and fast metabolism to decrease HQ cytotoxicity. The shorter microneedle contained fluocinolone acetonide to dissolve gently in the keratinocytes layer to eliminate the irritation. In vitro and in vivo study showed the feasibility of hyperpigmentation treatment. This approach could be a potential technology enabling direct transcutaneous delivery in clinical applications.