PK and tumor accumulation of C6CP and ETO in H69AR SCLC bearing mice. (a, b) Plasma (a) and tumor (b) biodistribution of both C6CP (black) and ETO (red) after single injection of various POx micelle formulations: C6CP/ETO PM (4/8/10), C6CP PM (4/10), and ETO PM (8/10) mixture, ETO PM (8/10), C6CP PM (4/10), and free ETO (Toposar). (c) C6CP and (d) ETO levels in accumulated in tumor 6, 24, and 48 h post-injection. Data are mean ± SD, * p < 0.05 (n = 3).