Plumbagin-Loaded Glycerosome Gel as Topical Delivery System for Skin Cancer Therapy

Plumbagin (PLM) is a phytochemical which has shown cytotoxicity against of cancer cells both in vitro and in vivo. However, the clinical application of PLM has been hindered due to poor aqueous solubility and low bioavailability. The aim of the present study was to develop, optimize and evaluate PLM-loaded glycerosome (GM) gel and compare with conventional liposome (CL) for therapeutic efficacy against skin cancer. The GM formulations were optimized by employing design expert software by 3-level 3-factor design. The prepared GMs were characterized in vitro for vesicle size, size distribution, zeta potential, vesicle deformability, drug release, skin permeation, retention, texture, antioxidant and cytotoxicity activities. The optimized formulation showed a vesicle size of 119.20 ± 15.67 nm with a polydispersity index (PDI) of 0.145 ± 0.02, the zeta potential of -27 ± 5.12 mV and entrapment efficiency of 76.42 ± 9.98%. The optimized PLM-loaded GM formulation was transformed into a pre-formed gel which was prepared using Carbopol 934 polymer. The drug diffusion fluxes of CL gel and GM-loaded gel were 23.31 ± 6.0 and 79.43 ± 12.43 µg/cm²/h, respectively. The result of texture analysis revealed the adequate hardness, cohesiveness, consistency, and viscosity of the developed GM-loaded gel compared to CL gel. The confocal images showed that glycerosomal gel has deeper skin layer penetration as compared to the control solution. GM-loaded gel treated rat skin showed significantly (p < 0.05) higher drug accumulation in the dermis, higher cytotoxicity and higher antioxidant activity as compared to CL gel and PLM suspension. Thus, findings revealed that novel GM-loaded gel could be potential carriers for therapeutic intervention in skin cancer.