Development and Characterization of Diosgenin-incorporated Nanoemulsion Gel System for Transdermal Drug Delivery

Nanoemulsion systems containing phytodrugs are efficient nanocarriers that can enhance the protective and bioavailability properties of poorly aqueous-soluble phyto-entities, thus, enhancing their use as transdermal drug delivery. This paper seeks to integrate distinctly the use of diosgenin (DG) into an oil-in-water (O/W) sub-micron-sized nanoemulsion (NE)/Nanogel (NeG) system that can increase its solubility in the transdermal therapeutic applications. Diosgenin-incorporated nanoemulsion (DGNe) was developed by the low-energy phase inversion composition (LE-PIC) technique. Excipients for NE preformulations, including sesame oil (SS) and bottle gourd (BG) seed oil, were screened for solubility and emulsifying ability. Pseudo-three-phase diagrams were plotted with BG seed oil and SS (BGSS) oil mix, including Tween 80 and glycerol as surfactant/cosurfactant mix. Using the Box Behnken design, optimum responses from 13 randomized NE preformulations were determined from particle size (nm), drug release (%), viscosity (cps), and pH. A Scanning Electron Microscope (SEM) and a Field Emission Scanning Electron Microscope were used to determine the characteristic surface morphology of DGNe and DGNeG. Differential Light Scanning Calorimeter (DLS) was used to determine the particle size, zeta potential, and polydispersity index (PDI) of DGNe. Fourier Transform Infrared (FT-IR) and DLS were used to determine the functional stability of the formulated DGNe and DGNeG. The outcome of the SEM indicated a near-spherical nanoemulsion matrix of diosgenin that was dispersed. DLS analysis revealed that the particles were between 82 -265 nm with a PDI of 0.01-0.40, and in the FT-IR technique, DGNe and DGNeG formulation were stable at day 0 and 90. It was also established that DGNe remained thermodynamically stable at 25 °C and 4 °C after 4 weeks. The viscosity result of DGNe showed that viscosity decreases with the increase in its water content. According to the in-vitro release profile, a slow release of the drug happened within 0.5 to 15 h. These results indicate a novel diosgenin-loaded nanoemulsion/nanogel system with interesting physicochemical and stability characteristics, prolonged release behavior needed for an effective transdermal delivery systems and therapeutic bioavailability of diosgenin.