(A) Release profiles of DOX in PBS buffer (pH 7.4, 0.14M NaCl) at 37 °C. (■) cl-PEG-b-PPGA nanogels, (□) cl-PEG-b-PGA nanogels, (●) non-cross-linked PEG-b-PPGA30 micelles, and (○) free DOX.
(B) Release profiles of DOX from cl-PEG-b-PPGA nanogels and non-cl-PEG-b-PPGA micelles. in PBS buffer (pH 7.4, 0.14M NaCl) and ABS buffer (pH 5.5, 0.14M NaCl) at 37°C. (■) cl-PEG-b-PPGA nanogels, pH 7.4, (□) cl-PEG-b-PPGA nanogels, pH 5.5, (◆) cl-PEG-b-PPGA nanogels in the presence of cathepsin, pH 5.5, The loading amount of DOX for each sample is 200 μg. Data are expressed as the mean ± S.D. of three independent measurements.