Formation strategies, mechanism of intracellular delivery and potential clinical applications of pH-sensitive liposomes

pH-sensitive liposomes are designed to specifically triggered release the loaded drugs in response to the change of pH in the surrounding serum. So pH-sensitive liposomes can effectively deliver drug or gene fragments into the cytoplasm via the endocytotic pathway. Furthermore, pH-sensitive liposomes can be successfully used in clinical if they enable the encapsulated drugs to be targeted to pathological tissues (such as primary tumors, metastases, local ischemia, inflammation and infection) of the body in which pH is less than the normal physiological value. That's the reason why a growing amount of literatures described the development and applications of pH-sensitive liposomes to improve the therapeutic index of the encapsulated active ingredients. In this review, the commonly used pH-sensitive molecules for pH-sensitive liposome and the mechanisms of intracellular delivery of pH-sensitive liposomes were addressed. Besides, the potential clinical applications were fully discussed in detail with an expectation to contribute to the clinical research of pH-sensitive liposomes.