A Quaternary Solid Dispersion System for Improving the Solubility of Olaparib

Abstract

To improve the low solubility of poorly water soluble olaparib, in the following study, we prepared olaparib-loaded quaternary solid dispersions with hypromellose, Tween 20 or Labrasol, and colloidal silica. The solubility of olaparib with various types of surfactants was evaluated to select the most suitable surfactant to effectively enhance its solubility, and subsequently, olaparib-loaded quaternary solid dispersions were prepared through spray drying. The physicochemical properties of the prepared olaparib-loaded quaternary solid dispersions were investigated using scanning electron microscopy, flowability, powder X-ray diffraction, and Fourier-transform infrared spectroscopy. The particle size of the olaparib-loaded quaternary solid dispersions was smaller and more spherical compared to the olaparib drug powder and maintained an amorphous state, and olaparib exhibited no intermolecular interactions with other excipients within the solid dispersion. Additionally, they exhibited enhanced flow properties compared to the olaparib drug powder. The results of subsequent kinetic solubility tests and dissolution tests demonstrated that the surfactant influenced the enhancement of the solubility and drug release of olaparib. Therefore, olaparib-loaded quaternary solid dispersions, characterized by enhanced solubility, will be beneficial for the oral delivery of poorly soluble olaparib. © 2025 by the authors.