In the present investigation, a nanoemulgel of minocycline was formulated and optimized for an improved drug delivery and longer retention time in the targeted area. Combining eucalyptus oil, Tween 20, and Transcutol HP, different o/w nanoemulsions were formulated by the oil phase titration method and optimized by pseudo-ternary phase diagrams. The morphology, droplet size, viscosity, and refractive index of the thermodynamically stable nanoemulsion were determined. Furthermore, optimized nanoemulsion was suspended in 1.0% w/v of Carbopol 940 gel to formulate the nanoemulgel, and for this, pH, viscosity, and spreadability were determined and texture analysis was performed. To compare the extent of drug penetration between nanoemulsion and nanoemulgel, ex vivo skin permeation studies were conducted with Franz diffusion cell using rat skin as the permeation membrane, and the nanoemulgel exhibited sustained-release behavior. It can be concluded that the suggested minocycline-containing naoemulgel is expected to treat acne rosacea more effectively.

Thymoquinone has a multitude of pharmacological effects and has been researched for a wide variety of indications, but with limited clinical success. It is associated with pharmaco-technical caveats such as hydrophobicity, high degradation, and a low oral bioavailability. A prudent approach warrants its usage through an alternative dermal route in combination with functional excipients to harness its potential for treating dermal afflictions, such as psoriasis. Henceforth, the present study explores a nanoformulation approach for designing a fulvic acid (peat-sourced)-based thymoquinone nanoemulsion gel (FTQ-NEG) for an enhanced solubility and improved absorption. The excipients, surfactant/co-surfactant, and oil selected for the o/w nanoemulsion (FTQ-NE) are Tween 80/Transcutol-P and kalonji oil. The formulation methodology includes high-energy ultrasonication complemented with a three-dimensional/factorial Box–Behnken design for guided optimization. The surface morphology assessment through scanning/transmission electron microscopy and fluorescence microscopy revealed a 100 nm spherical, globule-like structure of the prepared nanoemulsion. Furthermore, the optimized FTQ-NE had a zeta potential of −2.83 ± 0.14 Mv, refractive index of 1.415 ± 0.036, viscosity of 138.5 ± 3.08 mp, and pH of 5.8 ± 0.16, respectively. The optimized FTQ-NE was then formulated as a gel using Carbopol 971^® (1%). The in vitro release analysis of the optimized FTQ-NEG showed a diffusion-dominant drug release (Higuchi model) for 48 h. The drug permeation flux observed for FTQ-NEG (3.64 μg/cm²/h) was much higher compared to that of the pure drug (1.77 mg/cm²/h). The results were further confirmed by confocal microscopy studies, which proved the improved penetration of thymoquinone through mice skin. Long-term stability studies of the purported formulation were also conducted and yielded satisfactory results.