The GEN is a naturally occurring isoflavone. It is TKI and topoisomerase II inhibitor. It also exhibits anti-tumor, anthelmintic and anti-inflammatory properties . Like DSA, VOR and BTZ, upon Ra calculation, the hydrophilic pMeOx was supposed to show higher compatibility for GEN in comparison to hydrophobic blocks while for hydrophobic blocks, the estimated compatibility was in the order of pBuOx > pPentOx > pBuOzi > pPrOzi (Figure ). The experimentally determined GEN solubility in water was found to be 0.007 g/L (Table ). The formulation experiments revealed, at 6 g/L feed, both A-pBuOx-A and A-pBuOzi-A were capable to solubilize around 4.2 (LC ≈ 29 wt.% and LE ≈ 70%) and 4.3 g/L (LC ≈ 30 wt.% and LE ≈ 71%) of GEN, respectively (Figure ). A direct relationship was observed between GEN feed and solubilized GEN up to 6 g/L feed for all the triblock copolymers, with the exception of A-pPentOx-A (for which a slight decrease in GEN solubility was observed), while with the further GEN increase, the solubilizing capacity for all the triblock copolymer dropped to around 1.3 g/L. At 2, 8 and 10 g/L GEN feed, no significant differences in solubility was observed for all the four triblock copolymers. However, at 4 and 6 g/L GEN feed, higher level of polymer drug specificity can be observed. The compatibility results obtained by Ra calculation are partially consistent with the formulation results. As predicted, the A-pBuOx-A exhibited higher solubilizing capacity for GEN, but at the same time A-pBuOzi-A, which was predicted as third best solubilizer also showed similar solubilizing capacity like A-pBuOx-A at 6 g/L feed. While the A-pPentOx-A being predicted as second best solubilizer, appeared last in the row with the least formulation efficiency.