NCIt definition : An orally available nanoparticle-based formulation containing the hydrochloride salt
form of gemcitabine, a broad-spectrum antimetabolite and deoxycytidine analogue, with
antineoplastic activity. The formulation consists of an oil-in-water emulsion in which
gemicitabine is solubilized in the excipient matrix containing a mixture of oil and
(co)surfactants. Upon oral administration, gemcitabine is converted into the active
metabolites difluorodeoxycytidine diphosphate (dFdCDP) and difluorodeoxycytidine triphosphate
(dFdCTP) by deoxycytidine kinase. dFdCTP competes with deoxycytidine triphosphate
(dCTP) and is incorporated into DNA, resulting in premature termination of DNA replication
and the induction of apoptosis. Further, dFdCDP inhibits ribonucleotide reductase
and reduces the deoxynucleotide pool available for DNA synthesis. Compared to gemcitabine
alone, the emulsion allows for increased oral bioavailability and decreases its susceptibility
to deamination and deactivation by cytidine deaminase.;