Detailed Physicochemical Analysis of Hyaluronic Acid and Transferrin Self-Assembly To Produce Drug Carrier Colloids

Polyelectrolyte complexes (PECs) are polymeric nanostructures created by the self-assembly of oppositely charged macromolecules. PEC-based novel biomaterials are currently being researched as controlled drug delivery vehicles due to their unique combination of beneficial properties. In this work, the formation of a new colloid system composed of human apo-transferrin (Tr) protein and high-molecular-weight hyaluronic acid (HyA) polysaccharide was studied from numerous perspectives because, to the best of our knowledge, no information is available regarding this PEC-based Tr-HyA formula. For detailed characterization, the experimental results of several physicochemical and colloid chemistry techniques, such as light scattering, rheology, titration microcalorimetry, and electron microscopy, were analyzed. It was emphasized that the pH and mass ratio of the macromolecules greatly influence the self-assembly process. Particles with enhanced stability were prepared at a Tr/HyA = 2:1 mass ratio. The applicability of these colloid particles with a diameter of 240-260 nm as drug delivery vehicles was evaluated by encapsulating several practically water-insoluble molecules to increase their solubility in water. We highlighted that the nanoformulation revealed ca. 3 times better solubility and enhanced release for vitamins D3 and K1 compared to the unformulated ones.