Green Hydrogels Prepared from Pectin Extracted from Orange Peels as a Potential Carrier for Dermal Delivery Systems

Recycling fruit waste, like orange peels, into a green, eco-friendly, low-cost, and sustainable product is an effective way to reduce fruit waste. Pectin is a natural polymer extracted from citrus peels. It is widely utilized as a gelling agent, stabilizer, thickener, emulsifier, and rheology modifier. This study aimed to develop green gels from pectin extracted from orange peels as a carrier for topical preparations. The extracted pectin was characterized by a yield% of 14%, a degree of esterification of 20%, an equivalent weight of 2500 g/mol, a methoxyl content of 14.88%, and a galacturonic acid content of 91.52%. Additionally, the ethanolic orange peel extract was also prepared and compared with pectin hydrogels. Hydrogels were prepared using 8, 16, and 32% pectin concentrations, cross-linked with 0, 20, 40, 60, and 80% CaCl₂ concentrations, while the pH of the hydrogel was adjusted to 3.5 and 8.5. Pectin hydrogels exhibited pseudoplastic behavior, viscoelastic properties with elastic modulus <i>G</i>' dominating the viscous modulus <i>G</i>″, and bioadhesive properties. Moreover, the aqueous and ethanolic extractions of pectin from orange peels demonstrated a concentration-dependent antioxidant activity. Pectin hydrogels did not demonstrate wound healing or antimicrobial activities. In contrast, the ethanolic orange peel extract demonstrated improved wound healing, antimicrobial activity against the Gram-positive bacteria <i>Staphylococcus aureus</i>, and antioxidant activity. Therefore, the pectin hydrogel could serve as a potential carrier for dermal delivery systems. Moreover, the ethanolic orange peel extract has demonstrated potential as a dermal drug delivery carrier in wound healing and antimicrobial and antioxidant agents.