Differential scanning calorimetry as a tool to investigate the transfer of anticancer drugs to biomembrane model

Different anticancer drugs clinically approved by international regulatory organizations present poor water solubility and low stability after systemic injection. Their administration requires suitable carriers capable of maximizing therapeutic efficacy. Lipid and polymeric nanotherapeutics, particularly liposomes, are widely used to deliver chemotherapeutics in the clinic. The interaction between chemotherapeutics and biocompatible lipids and polymers can affect their efficacy and play a pivotal role in chemotherapy. Phospholipids are the main components of liposomes and their interactions with therapeutic agents are widely investigated in the pharmaceutical field using differential scanning calorimetry (DSC). In this work, DSC was exploited to investigate the interaction between hydrophobic chemotherapeutics, i.e. docetaxel, tamoxifen and lapatinib, with lipid vesicles. Lipid carriers are prepared using dimyristoylphosphatidylcholine (DMPC), a phosphatidylcholine derivative, showing the same physicochemical features of the main lipids in the biological membranes. DMPC was used as a biological membrane model to evaluate interaction, passage, diffusion, and adsorption of chemotherapeutics. These processes were evaluated through the variation of thermotropic parameters of the biological membrane model. DSC studies were carried out in heating and cooling mode. Results demonstrated a modification of calorimetric curves and this effect is strictly related to the molar fraction and physicochemical features of chemotherapeutics. Furthermore, the interaction between chemotherapeutics and biological membranes affects their internalization and distribution inside tumors and this process depends on gel-liquid crystal transition of phospholipids. DSC results provide suitable information about this effect and can be used as tool to predict further interaction between chemotherapeutics and biological membranes.