Fig. 3.

Kinetics of doxorubicin loaded polymersomes. (A) Cumulative in situ release of doxorubicin, loaded within 200 nm diameter PEO(2 K)-b-PCL(12 K)-based polymersomes, under various physiological conditions (pH 5.5 and 7.4; T = 37 °C) as measured fluorometrically over 14 days. N = 4 samples at each data point; individual data points for each sample varied by less than 10% of the value displayed at each time interval. (B) Release rates of DOX (V_dox) from 200 nm diameter PEO(2 K)-b-PCL(12 K)-based polymersomes vs. time. Dotted and solid lines represent exponential fits obtained by regression analysis (R² = 0.99 for each curve), and the displayed equations correspond to the respective release regimes (α, β, β′). (C) Schematic illustrating differing regimes of DOX release via (α) intrinsic drug permeation through intact vesicle membranes vs. (β and β′) release predominantly by PCL matrix degradation. [This image was reproduced from Ghoroghchian et al. [10] with permission from Copyright (2006) American Chemical Society.]