Uptake of Dox into LnCAP tumors. NOD/SCID mice bearing LnCap tumors were injected with saline (none) or Dox-HCL preparations (100 mg/kg) as indicated. Animals were euthanized 1 hour later, Dox extracted as described in Materials and Methods, the fluorescence was read at 560 nm, and the results normalized to tumor weight (*p < 0.005). Dox, doxorubicin; LNP, lipid nanoparticle; NOD/SCID, non-obese diabetic severe combined immune deficiency.