Chitosan/sodium dodecyl sulfate microcapsules preparation: Influence of applied method

This study aims to compare and analyse the synthesis of microcapsules stabilized with chitosan/sodium dodecyl sulphate complex according to emulsion preparation methods. For this purpose, 20 % oil-in-water emulsions were obtained in two ways: by emulsifying the oil phase in aqueous solution of chitosan and its mixtures with anionic surfactant (?method I?) and by subsequently dropping chitosan into an already prepared emulsion stabilized by anionic surfactant (?method II?). Good stability, positive zeta potential of the emulsions and uniform droplet size distribution obtained with both methods, enabled the preparation of chitosan-based microcapsules which were separated by spray drying and investigated in terms of yield, moisture content, particle mean diameter and size distribution. The results showed a uniform particle size distribution and approximately equal mean diameters of emulsion droplets (? 8 ?m), i.e., suspension particles (? 5?m), while the microcapsule yields and moisture content for method I were 15 and 1.14 %, and for method II were 1.2 and 2.85 %, respectively. These results indicate that method I may be more suitable for use in the pharmaceutical and food industries for the production of chitosan microcapsules with oil content. The study confirmed that small variations in preparation can lead to large changes in the microencapsulation process and microcapsule structure.