Figure 7: Containment of doxorubicin over time in drug-loaded liposomal vehicles. Containment studies of loaded HPLNs versus conventional PEG-liposomes showed that leakage increased significantly with time (), with geometric means at 4 hours, 1 day, and 6 days being, respectively, 0.9%, 4.6%, and 3.1% for conventional doxorubicin-loaded PEG-liposomes and 1.2%, 3.2%, and 5.9% for HPLN. There were no significant differences between the vehicles or the effects of pH or temperature that could be detected at 4 hours or 1 day. However, at 6 days HPLN had 1.9-fold greater overall leakage than DOX (; 95% C.I. 1.6- to 2.4-fold). Lowering pH from 7.4 to 4.5 increased leakage by a factor of 1.5 (; 95% C.I. 1.1- to 2.1-fold) with enhanced leakage at 37 degrees compared to 4 degrees ().