Topical Gemcitabine Hydrochloride

**Semantic type:** Pharmacologic Substance

**Definition:** A topical preparation of gemcitabine hydrochloride with antineoplastic activity. Gemcitabine, an analogue of the antimetabolite nucleoside deoxycytidine, is converted intracellularly to the active metabolites difluorodeoxycytidine di- and triphosphate (dFdCDP, dFdCTP). dFdCDP inhibits ribonucleotide reductase, thereby decreasing the deoxynucleotide pool available for DNA synthesis; dFdCTP is incorporated into DNA, resulting in DNA strand termination and apoptosis.