Self-assembled gel microneedle formed by MS deep eutectic solvent as a transdermal delivery system for hyperpigmentation treatment

Hyperpigmentation (HP) is an unfavorable skin disease that typically caused by injury, inflammation, or photoaging and leads to numerous physical and psychological issues in patients. Recently, development and application of natural whitening substances, particularly compound curcumin (CUR), is one of the most prevalent treatments for HP. However, it is still a formidable challenge to improve the percutaneous delivery of CUR due to its inadequate solubility in water and excellent barrier function of skin. To overcome the limitations of conventional delivery and increase the percutaneous absorption of CUR, the efficient delivery of CUR is urgently required. Herein, we developed a new malic acid-sorbitol deep eutectic solvent (MS/DES) gel microneedle loaded with CUR as a transdermal delivery system for HP treatment. The MS/DES gel produces three-dimensional (3D) network structure by self-assembly of hydrogen bond interactions, which conferred the CUR-MS/DES-GMN with sufficient mechanical properties to successfully penetrate skin tissue while also helping to enhance the drug's release rate. The CUR-MS/DES-GMN exhibit high biocompatibility and mechanical property in vivo of mice. The zebrafish experiments also show that CUR-MS/DES gel has significant effect of anti-pigmentation. Therefore, the designed CUR-MS/DES-GMN system provides a novel strategy for HP treatment based on self-assembly of naturally molecules.