Hydrolysis of CPT alone (○, dashed), loaded in p[(SEA)50-b-(nBA)50] (▲, blue), p[(AA)48-b-(nBA)50] (●, black), and p-[(AA)106-b-(nBA)50] (■) nanoparticles after incubation in DPBS at pH 7.4 at 37 °C with 3.5% human serum albumin. (top) Representative HPLC traces of hydrolyzed (~9.2 min) and intact (11.3 min) CPT after 18 h. (bottom) CPT hydrolysis over time. CPT concentration was 0.1 mg/mL for all samples except for a free CPT sample at 0.025 mg/mL (red dashed line).