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 G' dominating the viscous modulus G″, 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 Staphylococcus aureus, 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.