<p>About 40% of new chemical entities (NCEs) manufactured by pharmaceutical companies are practically insoluble or poorly soluble in water. Solubility is the main challenge for researchers and formulation scientists. Class II and IV medications are classified as low solubility by the biopharmaceutical classification system (BCS). The solubility of these classes of drugs can be increased to enhance their bioavailability. Different methods are used to improve the solubility of low soluble products, including chemical and physical drug modifications and other techniques such as crystallization, particle size reduction, salt formation, nanonization, micronization, surfactant use, etc. The selection of solubility enhancement techniques depends on the characteristics of the drug, the site of absorption, and the necessary features of the dosage form. An outline of the effects of low water solubility and the primary methods used to improve the solubility of medications with low water solubility are given in this review. How the drug’s solubilization procedure and the biopharmaceutical classification system relate is also considered. This review article’s highlights provide information on several prospective and present modern technologies created to improve the solubility of poorly soluble drugs.</p>