CXB is a cyclooxygenase (COX2) inhibitor and a nonsteroidal antiinflammatory drug . According to Ra calculation, pPrOzi hydrophobic block was supposed to be most compatible, pPentOx/pBuOzi showed similar and intermediate while pBuOx should exhibit the least compatibility for CXB (Figure ). On the contrary, the A-pBuOx-A gave the maximum achievable aqueous solubility for CXB i.e. 4.8 g/L (at 6 g/L CXB feed) (LC ≈ 32 wt.% and LE ≈ 80%) (Figure ). The solubility of CXB was experimentally found to be 0.004 g/L (Table ). At 2 and 4 g/L CXB feed, all the triblock copolymers gave the similar solubility, except for A-pPentOx-A, which showed a slight decrease (≈ 3.8 g/L) in solubilizing CXB at 4 g/L feed. Above 6 g/L feed, all the four triblock copolymer showed different solubilizing capacity and a general decrease in solubility for CXB was observed. Compared to other triblock copolymers, a dramatic decrease was observed in the case of A-pPrOzi-A triblock copolymer (solubility of CXB dropped to 0.1 g/L). The compatibility results for CXB are not consistent with the formulation experiments. The triblock copolymer concentration was kept constant at 10 g/L with the increasing feed of drug from 2 to 10 g/L. The triblock copolymers are represented according to their hydrophobic blocks only. All the formulation were prepared in triplicate and the results are presented as means ± standard deviation.