limited due to several issues such as stability, toxicity and drug resistance. Herein, we present the design and synthesis of a series of gemcitabine prodrugs with modifications on the 4-N-amino group by employing an acetylated L- or D-lysine moiety masked by different substitutions. Prodrugs 1–3 and 6–8 showed up to 2.4 times greater anticancer activity than gemcitabine in A549 lung cells, while they