Unusual solubilization capacity of hydrophobic drug olanzapine in polysorbate micelles for improved sustained drug release

•Polysorbate T20 and Polysorbate T20-Pluronic P84 mixed micelles accommodates a higher amount of hydrophobic drug Olanzapine.•Isothermal titration calorimetry confirmed the higher binding capacity of Olanzapine with Polysorbate T20.•SANS measurements suggested that the solubilization capacity of Polysorbates is also dependent upon aggregation number.•Both pure Polysorbates and Polysorbate-Pluronic P84 micelles showed the sustained release behavior.•This research output has a wider scope in colloidal chemistry as well as in pharmaceutical industry and manufacturing.