NANOFORMULATION OF BUDDLEJA DAVIDII EXTRACT: DEVELOPMENT AND CHARACTERIZATION OF LIPOSOMES AND NANOFIBERS FOR WOUND HEALING APPLICATION

In the current research project, Buddleja davidii plant extract containing verbascoside (VRB) was used as a potential wound healing agent in nanocarrier formulations for targeted delivery. We aimed to present a literature review, as well as experimental approaches involving two different nanocarrier formulations: liposomes and electrospun nanofibers, in understanding their impact on the stability, sustained delivery, and biocompatibility of wound healing ingredients. The Chapter 1 of the thesis discussed current approaches to wound care using nanocarriers, particularly liposomes and electrospun nanofibers, as drug delivery systems. This part emphasizes the importance of materials and structures in stabilizing sensitive bioactive molecules and drugs, extending their retention at the wound site, and controlling their release profiles. It serves as the background for the use of botanical extracts and nanotechnology in overcoming the challenges of traditional topical therapies. In Chapter 2, BD-extract loaded liposomes were formulated as a nanoscale delivery system using direct sonication method, later the formulations were characterized in terms of vesicle size, polydispersity index, and zeta potential. Encapsulation efficiency and verbascoside release profiles were assessed by HPLC, while antioxidant activity was also evaluated. Formulation stability was monitored for two months, and in vitro biocompatibility and antioxidant protective effects were investigated in human keratinocyte (HaCaT) cells. The liposomal formulations exhibited suitable physicochemical properties, high encapsulation efficiency, and good colloidal stability over time. Encapsulation preserved the antioxidant activity of the extract and ensured excellent biocompatibility across a wide concentration range. Prominently, liposomal incorporation modulated the release kinetics of verbascoside, limiting its rapid release in the wound aqueous environment and enabling a prolonged availability. In Chapter 3, empty and BD-extract-loaded polymeric nanofibers were fabricated based on alginate-polyethylene oxide (ALG-PEO) and polyvinyl alcohol-alginate (PVA-ALG) polymer blends. Electrospinning parameters such as applied voltage, flow rate, tip-to-collector distance, and environmental conditions (temperature and relative humidity) were optimized to obtain uniform, bead-free nanofibrous mats. The resulting nanofibers were characterized for drug loading efficiency through HPLC analysis, morphological analysis (through scanning electron microscopy), and swelling (water absorption) capacity. Moreover, in vitro release profiles were evaluated employing Franz diffusion cells simulating physiological conditions. We successfully fabricated uniform, reproducible mats and they exhibited time-dependent swelling and controlled VRB release up to 24 h. Overall, these findings support the potential inclusion in both delivery systems for controlled release, and nanofibers as wound-dressing matrices for localized delivery of plant-derived bioactives in wound care therapies, particularly for chronic wounds.