Gemcitabine prodrugs and uses thereof

A method for treating cancer selected from the group consisting of pancreatic cancer, non-small cell lung cancer, breast cancer, ovarian cancer, bladder cancer, and colorectal cancer in a subject in need thereof by inhibiting the growth of cancer cells, the method comprising administering to the subject an effective amount of a pharmaceutical composition comprising a compound according to formula I:

• or a pharmaceutically acceptable salt thereof;
• wherein
• R1 and R2 are independently selected from the group consisting of H, —C(═O)—(CH2)2—Ar and —C(═O)—(CH2)n—C(═O)—NH—Ar, and at least one of R1 and R2 is other than H, and Ar is aryl or heteroaryl;
• R3 is selected from the group consisting of H and —C(═O)—O—R4;
• R4 is selected from the group consisting of alkyl, substituted alkyl, alkenyl, substituted alkenyl, alkynyl, substituted alkynyl, arylalkyl, substituted arylalkyl, cycloheteroalkyl, substituted cycloheteroalkyl, heteroalkyl and substituted heteroalkyl;
• and
• the subscript n is an integer of from 2 to 6.