Curcumin loaded nanostructured lipid carriers for enhanced skin retained topical delivery: optimization, scale-up, in-vitro characterization and assessment of ex-vivo skin deposition

Nanostructured lipid carriers (NLC) have become a promising drug delivery system for topical delivery of drugs. Delivery of lipophilic drugs with improved stability and entrapment efficiency is one of the foremost benefits of NLC based formulations. The objective of the present study was to improve the permeation of poorly soluble curcumin into topical skin layers for the treatment of chronic inflammatory disorder psoriasis and microbial mediated acne vulgaris. Hot emulsification followed by probe sonication method was employed for the pre-paration of the curcumin loaded NLC. Further, in-vitro and ex-vivo characterization was performed for designed NLC. The designed NLC showed a mean particle size 96.2 +/- 0.9 nm, entrapment efficiency of 70.5 +/- 1.65% and zeta potential of-15.2 +/- 0.566 mV. Curcumin-NLC showed extended in-vitro release upto 48 hours, whereas free curcumin showed 100% drug release within 4 hours. Ex-vivo skin permeation studies revealed 3.24 fold im-proved permeation and skin retention in the case of curcumin loaded NLC gel compared to free curcumin gel. The cell viability studies demonstrated the formulation components showed no toxicity towards keratinocyte cells. In keratinocyte cells, improved cell uptake was observed for curcumin-NLC compared to free curcumin dispersion. The results suggested that the NLC based formulation had potential to improve the efficacy of cur -cumin.