The comparison of pure and newly-formulated epigenetic drugs using EPISSAY. Flow cytometric assessment of LT1 cells treated with epigenetic drugs. Treatments were: liposomal formulated or pure decitabine 1, 5, 10, 30 μM and/or pure vorinostat 1, 2 μM; pure zebularine 250, 500 μM; pure RG108 10, 100 μM (A) with or (B) without media change for 72 hours in triplicate. The gated geometric mean values of FL3-H (red-fluorescence) were normalized to the vehicle control, drug-free liposomes and water. Lipo: multilamellar decitabine-loaded liposomes; E-lipo: unilamellar decitabine-loaded liposomes. Pure: drug without modification. Unpaired two-tailed t-test, data expressed as mean ± SEM. * = p < 0.05, ** = p < 0.01, *** = p < 0.001, **** = p < 0.0001.