Solubility Enhancement Techniques: A Comprehensive Review of Approaches for Poorly Soluble Drugs

Aqueous solubility is one of the crucial factor that affect drug’s bioavailability. In order to achieve the intended pharmacological action, it is crucial to attain the the optimal concentration of the drug in the bloodstream. Almost 50% of the newly discovered drugs are found to be insoluble during the screening phase. Delivery of drugs and formulation development are restricted by poor solubility. Diverse techniques have been explored to improve the drug's water solubility. Since majority of drugs are poorly soluble, this review article focuses mostly on those that fall within classes II and IV of the Biopharmaceutical Classification System (BCS). Several techniques are described to improve the solubility of poorly soluble drugs, including solid dispersions, inclusion complexation, dendrimers, nano-suspensions, co-solvency, pH modification approach, self-emulsifying drug delivery system, hydrotrophy, co-crystallization, and ionic liquid creation.