After 24h at 4°C, the stock solutions were placed at room temperature. Since CyP-OBu was poorly soluble in water, the unencapsulated molecules precipitated. 200µL of the supernatant of each stock solution was mixed with 1.8 mL of ethanol. The mixture was shaken for 5 min at room temperature and then analyzed by UV-Vis spectroscopy with the equipment and following the protocol previously described. The concentration of encapsulated E-CyP-OBu is determined using the Lambert-Beer law and the approximation that molar absorption coefficients of the molecule solubilized in 100% ethanol or in an ethanol/water mixture (9/1) were similar. The encapsulation efficiency (EE) of E-CyP-OBu entrapped within liposomes was calculated by the Eq. ( ). The encapsulation rate (ER) was calculated according to the Eq. ( ):