Review on Solubility Enhancement Techniques in Pharmaceutical Formulations

Poor aqueous solubility is a major challenge in pharmaceutical formulation development, as it directly affects drug dissolution, absorption, and bioavailability. A significant proportion of newly developed drug molecules exhibit low water solubility, leading to formulation difficulties and reduced therapeutic effectiveness. To address this issue, a wide range of solubility enhancement techniques have been explored and implemented in pharmaceutical sciences. This review provides a comprehensive overview of conventional, advanced, and emerging approaches used to enhance the solubility of poorly water-soluble drugs in pharmaceutical formulations. Various physical, chemical, and formulation-based strategies such as particle size reduction, solid dispersion, salt formation, pH adjustment, complexation, surfactant-based systems, lipid-based drug delivery systems, nanotechnology-based approaches, and other novel techniques are discussed. Additionally, alternative and supportive approaches including hydrotropy, amorphization, electrospinning, and the use of solubilizing excipients are highlighted. Understanding the principles, advantages, and limitations of these techniques is essential for selecting an appropriate solubility enhancement strategy and for improving the clinical performance of poorly soluble drugs. This review aims to serve as a valuable reference for researchers, formulators, and students involved in pharmaceutical formulation development.