pH sensitive liposomes

Provided is a pH-sensitive liposome capable of shifting the zeta potential of a liposome from plus to minus under an arbitrary pH condition within a predetermined range by adjusting the content ratio of a specific component constituting the liposome. To do. SOLUTION: A phospholipid, a steroid, an anionic substance, and an amphoteric substance are contained as membrane constituents, and the anionic substance is added in an amount of 0 to 20% by mass with respect to the whole membrane constituents. It contains 5 to 20% by mass of an amphoteric substance. When dispersed in an aqueous medium having the following pH conditions, the zeta potential of the liposome is positive at pH 5 or lower, negative at pH 8 or higher, and increased in pH value between pH 5-8. At the same time, we shifted from positive to negative. [Selection figure] None