This study employed ultrasonic extraction, column elution fractionation and supercritical anti-solvent (SAS) recrystallization in purifying and in preparing micro-sized particles containing zeaxanthin dipalmitate (ZDP) from the Lycium barbarum fruits. Column fractionation of the ultrasonic acetone extract coupled with the SAS process of the ZDP-laden ethyl-acetate solution enhanced the amount of ZDP to 931.5 mg/g in the SAS precipitates (about 64.9% recovery) compared to 72.25 mg/g from the ultrasonic extract alone. A two-factor experimental design by response surface method showed that feed concentration and feed flow rate were important for SAS in obtaining the highest purity and the smallest mean size of the ZDP particles. The purest ZDP compound (98.3%) also led to the proliferation of anti-hydrogen peroxide oxidation of human adult retinal pigment epithelial cells. (C) 2012 Elsevier B.V. All rights reserved.