Enhancing skin moisture and anti-aging by DL-α-tocopherol loading sodium alginate-based hydrogel microneedles

Effective skin moisturization is essential for combating age-related skin deterioration and maintaining overall skin health. This study investigates the development and characterization of DL-α-tocopherol-loaded sodium alginate (SA)-based hydrogel microneedles (MNs) using a polyethylene glycol diglycidyl ether (PEGDE) crosslinking strategy for sustained, non-invasive antioxidant delivery and enhanced skin hydration. Three hydrogel formulations, SAP1, SAP2 and SAP3, were prepared with varying PEGDE to SA molar ratios, resulting in distinct swelling behaviors and crosslinking densities. SAP1 exhibited the highest swelling ratio, while SAP3 showed the lowest, which influenced the drug release profiles. SAP1α provided the fastest drug release, while SAP3α demonstrated a slowest release. SAP2α was selected for in vivo evaluation based on their balanced DL-α-tocopherol release along with favorable mechanical strength and swelling properties. SAP2α MNs significantly increased skin moisture from 13% to 37% within 8 days, outperforming the control and blank groups. These results show the potential of SA-based hydrogel MNs for transdermal drug delivery for skin rejuvenation and anti-aging. The moisturizing effectiveness of SAP2α MNs suggests their strong clinical potential in dermatology and cosmetic treatments for combating skin aging and dryness.