Nurgül Kiziltaş

You have a substance that is poorly soluble in water and want to improve its solubility with Tween 20. It can solubilize the hydrophobic molecules of the substance in its micelles. You have already chosen Twin 20 for these purposes and its CMC and HLB have nothing to do with it. Which of your results do not agree with the text is not clear. Any surfactant will be adsorbed at the interface between two surfaces. For your case, a hydrophobic substance/water.

Tween 20 (also known as Polysorbate 20) is a nonionic surfactant that is commonly used in pharmaceutical and biotech industries. It is often used to solubilize hydrophobic compounds, such as your nanosuspension product, by forming micelles around them, which then allows the hydrophobic compound to remain in solution. However, as you have observed, Tween 20 can also adsorb at the hydrophobic molecule-water interface, which may interfere with the dissolution studies of your product and result in inconsistent results.

One solution to this problem is to use a different surfactant that has a lower tendency to adsorb at the hydrophobic molecule-water interface. For example, you could try using Polysorbate 80 (Tween 80) instead of Tween 20. Polysorbate 80 has a higher HLB (Hydrophilic-Lipophilic Balance) value than Tween 20, which means it is more hydrophilic and has a lower tendency to adsorb at the hydrophobic molecule-water interface. Alternatively, you could try using a different nonionic surfactant altogether, such as Pluronic F-127 or Cremophor EL.

Another approach to reducing the adsorption of Tween 20 on your hydrophobic molecule is to optimize the preparation of the dissolution medium. One way to do this is to ensure that the Tween 20 is fully solubilized in the medium before adding the hydrophobic molecule. You could also try pre-coating the nanosuspension particles with Tween 20 before adding them to the dissolution medium. This will help to prevent the surfactant from adsorbing at the hydrophobic molecule-water interface.

The HLB and CMC (Critical Micelle Concentration) values of Tween 20 can also affect its adsorption on hydrophobic molecules. The HLB value is a measure of the balance between the hydrophilic and lipophilic properties of a surfactant. A higher HLB value means the surfactant is more hydrophilic and less likely to adsorb at the hydrophobic molecule-water interface. The CMC value is the concentration at which a surfactant forms micelles in solution. If the concentration of Tween 20 in the dissolution medium is above its CMC value, the surfactant will form micelles around the hydrophobic molecule, which can help to solubilize it and prevent adsorption at the hydrophobic molecule-water interface.