Chitosan is a biodegradable, biocompatible, muco- adhesive and nontoxic natural polymer and has great potential for pharmaceutical application as drug and therapeutic enzyme carriers [6,7]. The physical and chemical properties of chitosan make this polymer also a rather attractive for encapsulation of thyme essential oil. It is a natural linear polysaccharide, obtained by alkaline deacetylation of chitin, which is a component of the protective cuticles of crabs, shrimps and other crustaceans and fungal mycelia [8]. Chitosan is soluble in acid conditions, but it has poor solubility above pH 6.5. It is structurally a linear polysaccharide composed of repeating units of β-(1-4)-2-amino-2-deoxy-D-gluco- pyranose (D-glucosamine), and has free amino groups on its polymeric chains. These amino groups protonate