A Multi-Component Nano-Co-Delivery System Utilizing Astragalus Polysaccharides as Carriers for Improving Biopharmaceutical Properties of Astragalus Flavonoids

Purpose: Enhancing the dissolution, permeation and absorption of active components with low solubility and poor permeability is crucial for maximizing therapeutic efficacy and optimizing functionality. The objective of this study is to investigate the potential of natural polysaccharides as carriers to improve the biopharmaceutical properties of active components. Methods: In this study, we employed four representative flavonoids in Astragali Radix, namely Calycosin -7-O-β-D- glucoside (CAG), Ononin (ON), Calycosin (CA) and Formononetin (FMN), as a demonstration to evaluate the potential of Astragalus polysaccharides (APS) as carriers to improve the biopharmaceutical properties, sush as solubility, permeability, and absorption in vivo. In addition, the microstructure of the flavonoids-APS complexes was characterized, and the interaction mechanism between APS and flavonoids was investigated using multispectral technique and molecular dynamics simulation. Results: The results showed that APS can self-assemble into aggregates with a porous structure and large surface area in aqueous solutions. These aggregates can be loaded with flavonoids through weak intermolecular interactions, such as hydrogen bonding, thereby improving their gastrointestinal stability, solubility, permeability and absorption in vivo. Conclusion: We discovered the self-assembly properties of APS and its potential as carriers. Compared with introducing external excipients, the utilization of natural polysaccharides in plants as carriers may have a unique advantage in enhancing dissolution, permeation and absorption. Keywords: astragalus polysaccharides, flavonoids, self-assembly, solubility, permeability, natural carrier