Electrostatic spraying for fine-tuning particle dimensions to enhance oral bioavailability of poorly water-soluble drugs

While spray-drying has been widely utilized to improve the bioavailability of poorly water-soluble drugs, the outcomes often exhibit suboptimal particle size distribution and large particle sizes, limiting their effectiveness. In this study, we introduce electrostatic spraying as an advanced technology tailored for poorly water-soluble drugs, enabling the fabrication of nanoparticles with fine and uniform particle size distribution. Regorafenib (1 g), as a model drug, copovidone (5 g), and sodium dodecyl sulfate (0.1 g) were dissolved in 200 ml ethanol and subjected to conventional-spray-dryer and electrostatic spray dryer. The electrostatic spray-dried nanoparticles (ESDN) showed smaller particle sizes with better uniformity compared to conventional spray-dried nanoparticles (CSDN). ESDN demonstrated significantly enhanced solubility and rapid release in water. <i>In vitro</i> studies revealed that ESDN induced apoptosis in HCT-116 cells to a greater extent, exhibiting superior cytotoxicity compared to CSDN. Furthermore, ESDN substantially improved oral bioavailability and antitumor efficacy compared to CSDN. These findings suggest that ESD shows potential in developing enhanced drug delivery systems for poorly water-soluble drugs, effectively addressing the limitations associated with CSD methods.