An object of the invention is to provide a dug carrier that is capable of regulating pharmacokinetics in vivo. The invention is directed to the drug carrier comprising a molecular assembly by which a dug is supported and the object can be achieved by releasing part of amphiphilic molecules constituting the molecular assembly from the molecular assembly due to external environmental change. A phenomenon in which the amphiphilic molecule is released from the molecular assembly because a hydrophilic-hydrophobic balance is shifted to hydrophilicity by external environmental change is utilized in the invention.
