Solubilizers are surfactants with solubilizing ability. Solubilization refers to the process of increasing the solubility of insoluble drugs in the solvent and forming a solution under the action of surfactants. The nature of the solubilizer, the nature of the solubilizer, the HLB value of the solubilizer, the temperature and the amount of the solubilizer are all factors influencing the solubilization effect. In the presence of surfactant colloidal particles, the process of increasing the solubility of insoluble drugs and forming a clarified solution is called solubilization. The surfactant used for solubilization is called solubilizer, such as the solubility of cresol in water is only about 3%, but in soap solution can be increased by 50% (i.e. cresol soap solution), where the soap is the solubilizer. Solubilized substances are called solubilizers. For water as the solvent of the drug, the most suitable HLB value of solubilizer is 15 18. commonly used solubilizers such as polysorbates and polyoxyethylene fatty acid esters.