Systematic development and characterization of curcumin-loaded nanogel for topical application.

Curcumin (CUR) conventional formulation has poor oral bioavailability due to low solubility and low stability. Also, it extensively undergoes first-pass-metabolism showing low biological activity. The present work focuses on the systematic development and characterization of CUR-loaded Nanostructured Lipid Carrier (CUR-NLCs) having promising topical applications for skin diseases such as psoriasis. CUR-NLCs were prepared by using high-speed homogenization method. Quality by design approach was exploited to select out Critical Process Parameters i.e. homogenization speed (X1), homogenization time (X2), amount of lipid (X3), solid lipids (SL): liquid lipids (LL) (X4), and surfactant conc. (X5) using Plackett-Burman design and for obtaining critical quality attributes i.e. particle size (Y1) and entrapment efficiency (Y2) using Box-Behnken design. The developed NLCs were found to be nano-metric in size (189.4 ± 2.6 nm) with a low polydispersity index (0.262 ± 0.24), zeta potential (-21.45 ± 1.3 mV), and showed good encapsulation efficiency (86.72 ± 09%). Surface morphology determined by SEM and AFM revealed the spherical shape of the NLCs with a smooth surface. XRD studies showed NLCs in the amorphous state. After incorporation of NLCs into a nanogel, it was characterized for pH, rheological behavior, spreadability, in vitro occlusion, and in vitro release kinetics. The drug release from NLC in 24 h was found to be 60.2 ± 0.45% indicating a sustained release pattern. Ex vivo permeation studies revealed a good permeation flux (0.453 ± 0.76 µg/cm2.h) and retention (60.2 ± 0.45%) of CUR in the skin epidermis. Thus, developed CUR-NLCs can be a potential delivery system and a promising therapeutic approach for the effective treatment of psoriasis.