Preparation of uniform-sized colloidosomes based on chitosan-coated alginate particles and its application for oral insulin delivery.

Colloidosomes are microcapsules that consist of a hollow core coated by a shell composed of self-assembled colloidal particles. In recent years, they have attracted significant attention as potential vehicles for the controlled delivery of active ingredients. A key challenge in such applications is the production of uniform-sized colloidosomes for the encapsulation of active ingredients such that the actual delivery amount can be well controlled. Based on our previous study on an ethyl acetate-in-water emulsion stabilized by chitosan-coated alginate particles, we further prepared monodisperse colloidosomes with a high yield and low permeability by combining the premix membrane emulsification technique and polymer deposition method. The potential application of the formed colloidosomes as oral insulin delivery vehicles was investigated. Our results revealed that in comparison to conventional PLGA microspheres, the formulated colloidosomes showed high drug encapsulation efficiency (up to 96.7%) and an obvious pH sensitive release profile. Moreover, in animal testing, the colloidosomes formulation achieved a long-term hypoglycemic effect up to 6 h, which confirmed its application as an oral drug delivery system.