Preparation and evaluation of transdermal hydrogel of chitosan coated nanocurcumin for enhanced stability and skin permeability

Curcumin (CR) is a natural product that has great interest in biopharmaceutical applications. It has several biological effects that antagonizes inflammation, oxidative stress, and cancer. On the other hand, low aqueous solubility, stability, and dissolution rate are the main challenges to using curcumin. In the present investigation, curcumin was formulated as a nanosystem known as nanocurcumin using a combination of polyvinyl pyrrolidone (PVP) with different polymers as stabilizing agents. The nanocurcumin formulations were prepared and evaluated by measuring the particle size, surface charge, drug content, and stability. The selected nanocurcumin formulation prepared using PVPK30-Poloxamer 188 demonstrated a significantly smaller particle size (272.1 ± 15.32 nm) and a higher settlement volume ration as compared with other formulations. Also, the selected formulation showed higher solubility and dissolution rates as compared with other stabilizer combinations. Chitosan was added to the selected nanocurcumin formulation as a coating polymer to enhance short-term storage colloidal stability. The result of stability proved that chitosan (0.05%)-coated nanocurcumin dispersion showed good stability during storage as compared with non-coated nanocurcumin. Non-coated nanocurcumin and chitosan-coated curcumin were loaded into the Carbopol934 hydrogel matrix to investigate the effect on curcumin permeability across the skin. The results revealed that nanocurcumin hydrogel formulations showed a significantly higher amount of curcumin permeated across the skin.