Optimization of Astaxanthin microencapsulation in hydrophilic carriers using response surface methodology.

Astaxanthin (3, 3'-dihydroxy-β, β-carotene-4, 4'-dione; AST) belongs to class of xanthophylls and is very effective antioxidant. It has very poor aqueous solubility resulting in lower bioavailability which presents major concerns in product development for oral use. AST was microencapsulated with soluble polymers using spray drying to improve its solubility and bioavailability. Quality by Design (QbD), a widely used approach for prediction of quality for desired specifications and effects was applied Design of Experiments (DOE), a useful component of QbD was utilized to understand the effect of variables and their interactions. Different formulation variables like ratio of hydrophilic carriers, concentration of solubilizers and homogenizer speed were challenged in the experimental design during the process of microencapsulation. The optimized formulation showed consistent release rate and characterization was done by DSC, XRD and SEM study. Percent cell growth inhibition was increased in optimized formulation as compared to plain AST. This QbD study can form a basis for further development of poorly water soluble AST formulation by oral route with improved bioavailability on larger scale.