Doxorubicin (DOX) and Pluronic-PAA interaction was investigated using isothermal titration calorimetry (ITC). DOX/polymer interaction is governed primarily by electrostatic interaction. The uptake of DOX results in the formation of insoluble polymer/DOX complex. Addition of salt weakens the interaction of drug and polymer by charge shielding effect between positive ionized amino group on DOX and oppositely charged polymer chains. However high drug-loading capacity in high salt condition implied that self-association property of DOX also play a role in the drug loading process.Singapore-MIT Alliance (SMA)