Gelatin/Chitosan Bilayer Patches Loaded with Cortex Phellodendron amurense/Centella asiatica Extracts for Anti-Acne Application

Acne is a chronic inflammatory skin disease that often occurs with anaerobic Propionibacterium acnes (P. acnes). Anti-acne patches, made of hydrocolloid or hydrogel, have become a popular way of topical treatment. The outer water-impermeable layer of commercial patches might create hypoxic conditions and promote P. acnes growth. In this study, gelatin/chitosan (GC) bilayer patches were prepared at different temperatures that included room temperature (RT), -20 degrees C/RT, and -80 degrees C/RT. The most promising GC bilayer patch (-80 degrees C /RT) contained a dense upper layer for protection from bacteria and infection and a porous lower layer for absorbing pus and fluids from pimples. The anti-acne bilayer patch was loaded with Cortex Phellodendri amurensis (PA) and Centella asiatica (CA) extracts. PA extract could inhibit the growth of P. acnes and CA extract was reported to improve wound healing and reduce scar formation. Moreover, the water retention rate, weight loss rate, antibacterial activity, and in vitro cytotoxicity of the patches were investigated. The porous structure of the patches promoted water retention and contributed to absorbing the exudate when used on open acne wounds. The GC bilayer patches loaded with PA/CA extracts were demonstrated to inhibit the growth of P. acnes, and accelerate the skin fibroblast cell viability. Based on their activities and characteristics, the GC bilayer patches with PA/CA extract prepared at -80 degrees C/RT obtain the potential for the application of acne spot treatment.

Automated summary

The study prepared gelatin/chitosan (GC) bilayer patches at different temperatures, with the most effective one prepared at -80 degrees C/RT, showing potential for absorbing pus and fluids while inhibiting bacterial growth. The bilayer patches loaded with Cortex Phellodendri amurensis (PA) and Centella asiatica (CA) extracts demonstrated inhibitory effects on P. acnes growth and promotion of skin fibroblast cell viability, suggesting their potential for acne spot treatment.