Curcumin loaded liquid crystalline nanoparticles for enhanced topical application: Design, characterization, ex vivo and dermatokinetic evaluation

Despite its effectiveness, topical delivery of curcumin (CUR) is restrained by its limited aqueous solubility and inadequate skin retention and permeation. Through this research, the potential of curcumin-loaded lyotropic liquid crystalline nanoparticles (CUR-LCNP) embedded hydrogel has been explored to enhance CUR skin permeation and retention. Quality by design approach was used to optimize the formulation and was further characterized. The optimized formulation was embedded in a hydrogel and evaluated for various rheological parameters. Further, the selected batch was investigated for ex vivo skin permeation and retention studies followed by dermatokinetic evaluation. The CUR-LCNP showed an average particle size of 126.03 ± 17.49 nm, a polydispersity index of 0.32 ± 0.01, and an entrapment efficiency of 88.25 ± 2.98%. The CUR-LCNP displayed a sustained release for 48 h following first-order release kinetics. The ex vivo permeation study showed 0.830-fold more flux for drug permeation through FD gel than CUR-LCNP gel after 24 h whereas, the retention was found to be 2.57 and 3.52-fold greater in stratum corneum and viable skin layers with CUR-LCNP gel. The dermatokinetic study revealed a significantly high Cmax in the epidermis and dermis for LCNP gel with 40.05 and 1.46 μg/cm2 compared to FD gel with 20.08 and 0.71 μg/cm2. Using the intrinsic fluorescence property of CUR, the penetration of CUR-LCNP into the deeper layers of skin was also evaluated using Fluorescence microscopy. Also, the developed formulation showed acceptable rheological properties with the non-Newtonian flow and good spreadability for topical application with dermal localization via skin.