Figure 4.

Cytotoxicity studies show AD-DOX is comparable to unmodified DOX. DOX modified with an AD group attached by a pH-cleavable hydrazone bond was compared with regular, unmodified DOX and tested at 36, 10, 3.6, 1, 0.36, 0.1, and 0.036 μM. AD-DOX was observed to have an approximately equivalent cytotoxicity to DOX within most of tested concentration ranges. Statistically significant concentrations are labeled with asterisks where the t-value <0.01. At high concentrations, some differences at 10 μM AD-DOX were observed to be slightly more toxic, whereas at 36 μM DOX was observed to be slightly more toxic