Solid lipid nanoparticles for transdermal delivery of curcumin: Optimization using factorial design and in vitro characterization

This study aimed to design and optimize Curcumin (CUR) loaded solid lipid nanoparticle (SLNs) transdermal formulations by nano emulsion template method. A 3 factor, 2 level Box-Behnken design was used to evaluate the effect of three independent variables viz., Amount of Span 60 (X1), Tween 60 (X2) and Stearyl alcohol (X3) on dependent variables viz., Particle size (Y1), entrapment efficiency (Y2) and zeta potential (Y3). Optimization study signifies that amount of formulation components viz., Span 60, Tween 60 and Stearyl alcohol influence the vesicle size, entrapment efficiency and Zeta potential. The numerical optimization was validated within the design space. The OP-CUR-SLNs exhibited good entrapment efficiency and particle size. Further the OP-CUR-SLNs loaded transdermal carbopol gel shows good in vitro drug release and better ex vivo permeation than the plain CUR loaded gel, which concludes CUR-SLNs considered to be a successful topical transdermal drug delivery system and provide a sustained release of encapsulated drug. Furthermore, CUR-SLNs loaded carbopol gel considered to be non-irritant and safe to be applied on the skin for the intended period of time.