Upgrading skin barrier Protection: Addition of active ingredients to a Gelatin/Tannic Acid-Based hydrogel patch for...

Prolonged use of Personal Protective Equipment, like surgical masks, can cause skin issues such as acne ("maskne") and rosacea flare-ups due to pressure and moisture. While dressings can protect the skin, they often reduce mask effectiveness and lack pharmaceuticals to treat common skin lesions. This study introduces an innovative dual-function gelatin/tannic acid-based hydrogel patch incorporating metronidazole (1% w/w) or salicylic acid (2% w/w) to offer both skin protection and treatment. The hydrogels were characterized for gelation temperature, burst strength, extensibility, adhesivity, and tribological properties to assess the effects of the active ingredients on their mechanical performance. In vitro release studies using Franz diffusion cells under occlusive conditions evaluated the drug release profile from the patches. Results showed that gelatin/tannic acid and gelatin/tannic acid-metronidazole hydrogels had similar gelation temperatures (41.65 ± 1.95 °C), while the salicylic acid formulation exhibited a lower gelation temperature (33.24 ± 0.40 °C). Adhesivity improved with the addition of active ingredients, increasing by about 0.5 N, and burst strength significantly increased with metronidazole (about 6 N). Both formulations demonstrated enhanced extensibility and were suitable for all skin types in tribological studies. The in vitro release studies showed an initial burst release followed by controlled release, unaffected by mask placement. These findings suggest that dual-function hydrogel patches could provide effective skin protection and improve skin health during prolonged mask use, offering a promising solution for conditions like "maskne" and rosacea.