Liposomes are inherently thermo-responsive and their transition temperature (Tc) is composition dependent, with the length and degree of saturation of the phospholipid alkyl chain influencing the transition temperature . Upon heating above the Tc, a liposome will undergo a gel-to-liquid transition . In the ordered gel phase, the phospholipids are aligned and well-packed, forming a relatively impermeable barrier. Once the temperature exceeds the Tc the bilayer becomes a disordered, liquid crystalline phase that is more permeable and permits release of the entrapped drug .