Formulation Strategies for Transferosome-Loaded Calendula officinalis Ointment: An Experimental Wound Healing Study

Abstract

The present study aimed to develop and evaluate a transferosome-based topical ointment containing Calendula officinalis extract for enhanced wound healing efficacy. Transferosomes were prepared by the thin-film hydration method and optimized based on vesicle size, polydispersity index (PDI), zeta potential, and entrapment efficiency. The optimized formulation exhibited a vesicle size of 110.5 ± 5.2 nm, a PDI of 0.214 ± 0.03, and a zeta potential of –32.5 ± 2.8 mV, indicating uniform, stable, and nanoscale vesicles suitable for dermal application. The entrapment efficiency (82.4 ± 2.1%) confirmed efficient loading of the phytoconstituents. The optimized transferosomal suspension was incorporated into a simple ointment base (O4: DMSO 1% + Propylene Glycol 3%) and evaluated for physicochemical parameters, in vitro release, and in vivo wound healing in Wistar rats. The ointment demonstrated excellent spreadability, pH compatibility (5.9 ± 0.1), and sustained drug release (88.2% at 24 h) following zero-order kinetics. In vivo studies revealed significantly higher wound contraction (98.7% on day 14) compared to plain ointment (87.2%) and control (74.5%). Histopathological analysis showed well-organized collagen deposition, minimal inflammation, and complete re-epithelialization in the transferosomal group. The results establish that transferosomal delivery of Calendula officinalis extract significantly enhances dermal penetration, promotes tissue regeneration, and provides sustained therapeutic action, making it a promising nanocarrier-based approach for topical wound healing.