Tea saponins as novel stabilizers for the development of diosmin nanosuspensions: Optimization and in vitro evaluation

Diosmin (DSN) is a plant-origin polyphenolic component that has attracted considerable interest for various physiological applications. Nevertheless, DSN shows high intersubject variation and poor oral absorption because of its poor solubility and permeability. This study examined the use of phytosaponins, specifically, tea saponins (TS), as novel stabilizers for optimizing and preparing diosmin nanosuspensions using top-down methods. The main formulation and process variables in particle size and polydispersity index were investigated by single-factor experiment optimization. The DSN nanocrystals were prepared and then characterized by electron microscopy, Fourier transform infrared spectroscopy (FT-IR), and powder X-ray diffraction (PXRD). Compared with conventional stabilizers, TS exhibited better stabilizing performance at low concentrations. The lyophilized powder, which had a particle size 478.4 ± 9.4 nm after redispersion, coupled with mannitol as lyoprotectant showed good redispersibility. Electron microscopy revealed that the nanocrystals had an irregular and lamellar morphology. PXRD and FT-IR spectroscopy indicated that the crystallinity of DSN was reduced during the production process. DSN nanosuspensions significantly enhanced the accelerated dissolution rate due to the amorphous status and decreasing particle size. Overall, this study presents an advantageous solution to poor solubility and offers a reasonable strategy for expanding the application range of DSN.