This invention relates to novel compounds with skin lightening properties based on an aromatic hydrazine carboxyimidoamide structure, topical skin lightening compositions comprising the same and a method of skin lightening using the said compositions. In particular, the skin lightening benefit is selected from any one of the group consisting of treating melasma, treating post-inflammatory hyperpigmentation, treating age spots, treating dark spots and treating uneven skin tone.
Desired skin colour is a major unmet consumer need around the world and especially in Asia. Consumers particularly desire even skin colour, absence of age spots (solar lentigines), absence of hyperpigmentation and lighter overall skin tone. One solution is to use biological actives that reduce the activity of melanocyte cells in skin. These cells, present in the basal layer of the epidermis, make the dark coloured pigment melanin and export it, in small export vesicles called melanosomes, to the neighbouring keratinocytes. It is well described in the literature that compounds which reduce melanin synthesis when topically applied to the skin will reduce skin darkness over time and can generate a more even skin tone.
Tyrosinase is a very popular target for the regulation of melanocyte pigment production. However effective inhibitors of tyrosinase are bedevilled by safety issues causing, for example, melanocyte cell death, permanent depigmentation, irritation and allergic reactions. Often effective inhibitors kill melanocytes (for example hydroquinone) or cause sensitisation reactions. There is therefore a great need for safe and effective inhibitors of skin pigment production that work through an alternative safe mechanism.
The inventors have observed that selected compounds of the same generic structure inhibit the production of soluble melanin by B16 mouse melanoma cells without cell toxicity.
本发明涉及基于芳香族
肼羧亚
氨基酰胺结构的具有皮肤美白特性的新型化合物、包含上述化合物的局部皮肤美白组合物以及使用上述组合物的皮肤美白方法。特别是,皮肤美白功效可选自治疗黄褐斑、治疗炎症后色素沉着、治疗老年斑、治疗黑斑和治疗肤色不均中的任意一组。
期望的肤色是全世界尤其是亚洲消费者尚未满足的一个主要需求。消费者尤其希望肤色均匀,没有老年斑(日光性色斑),没有色素沉着,整体肤色较白。一种解决方案是使用
生物活性物质来降低皮肤中
黑色素细胞的活性。这些存在于表皮基底层的细胞制造深色色素
黑色素,并通过称为
黑色素小体的小出口囊泡将其输出到邻近的角质细胞。有文献详细描述,将减少
黑色素合成的化合物局部涂抹在皮肤上,随着时间的推移,会减少皮肤的暗沉,使肤色更加均匀。
酪氨酸酶是调节
黑色素细胞色素生成的常用靶标。然而,有效的
酪氨酸酶抑制剂却存在安全问题,例如会导致
黑色素细胞死亡、永久性色素沉着、刺激和过敏反应。有效的
抑制剂通常会杀死
黑色素细胞(如
氢醌)或引起过敏反应。因此,亟需安全有效的皮肤色素生成
抑制剂,通过另一种安全机制发挥作用。
本发明者观察到,具有相同通用结构的特定化合物可抑制 B16 小鼠
黑色素瘤细胞产生可溶性
黑色素,且不会对细胞产生毒性。