The present invention discloses a method for preparing alginate nanocapsules, including the steps of: (a) forming a water-in-oil emulsion including an alginate in water, an oil, and at least one nonionic surfactant and (b) separating the aqueous phase and oil phase to obtain the semisolid form alginate nanocapsules and (c) by ionically crosslinking the alginate with calcium ions to obtain a colloidal form of calcium alginate nanocapsules for drug delivery.
