Gemcitabine derivatives nanoparticles

2',2'-Difluoro-2'-deoxycytidine derivatives (I) are new. 2',2'-Difluoro-2'-deoxycytidine derivatives of formula (I) are new. R1-R3 each : hydrogen or hydrocarbyl acyl of at least 18C with a conformation that imparts the capacity for (I) to adapt a compacted form in polar solvent, provided at least one is other than hydrogen. Independent claims are also included for the following: (1) nanoparticles (NP) of (I); (2) method for preparing NP; and (3) use of squalenic acid (II), or its derivatives, for formulating at least one polar active agent of molecular weight over 100 as nanoparticles. [Image] - ACTIVITY : Cytostatic; Virucide. - MECHANISM OF ACTION : (I) is converted intracellularly into its triphosphate and when this is incorporated into replicating DNA, elongation is stopped, resulting in cell death.