Lutein-Loaded Solid Lipid Nanoparticles for Ocular Delivery: Statistical Optimization and Ex Vivo Evaluation

Purpose This study aimed to develop and optimize lutein-loaded solid lipid nanoparticles (Lu-SLN) for ocular delivery. The objective was to achieve the mean particle size of Lu-SLN less than 100 nm, sustain the drug release up to 8 h, and evaluate the corneal permeation parameters of the optimized batch. Methods Lu-SLN were prepared by hot homogenization and cold dilution method. The Plackett-Burman screening design and 3(2) full factorial design were adopted sequentially to study the effect of various formulation and process variables, and further optimized with the help of desirability function. Results The statistical designs revealed that the amount of Gelucire (R) 44/14 and homogenization speed had a significant effect (P < 0.05) on the mean particle size and % drug release of Lu-SLN. The optimized formulation prepared with the help of the desirability function showed a mean particle size of 79.70 nm and sustained the drug release up to 8 h in simulated tear fluid. The apparent permeability coefficient and steady-state flux of the optimized batch were found to be 1.09 x 10(-4) cm/h and 7.33 x 10(-2) mu g/cm(2)/h, respectively, and the corneal hydration was found to be 78.35%. Conclusions Lu-SLN with chosen objectives can be successfully prepared by hot homogenization technique and ex vivo evaluation revealed that optimized formulation avoided any damage to the cornea.