The Solvent Redistribution method

What is the Solvent Redistribution (SR) method?

The solvent redistribution (SR) method is based on observing the redistribution of the solvent in response to an external stimulus such as the addition of solutes, changes in pH, temperature or pressure. The solvent is not simply a background but a reactive medium that responds to the smallest amounts of external stimulus.

Solvent Redistribution method as applied to solubility and aggregation

Solubility is about the solute dissolving in the solvent. Its not only about the solute but also about the solvent molecules around the solute! The SR method utilizes how the solvent redistributes around the solute molecules (it can be solid, liquid or gas) to obtain information about the aggregation state of the solute clusters. Here we show the redistribution of the solvent at different stages of aggregation:

How does the SR method change the landscape of solubility measurements?

The SR method is introducing a fundamental change on how solubility and aggregation is measured. While typical methods focus on observing the solute, the SR method shifts its focus on the solvent itself, which by far, outnumbers the solutes thereby providing much more information. Small additions of solute is felt as a whole by the solvent molecules, making it sensitive to small additions (nanomolar concentrations) of solute. The solvent redistribution method is not limited to solubility measurements. It also applicable to aggregation, crystallization and stability of substances. It is valid for different types of samples  in different types of solvents. The only condition for the solvent is that the solvent must be dipolar (water or any aqueous-based biologically relevant media, DMSO, methanol, ethanol, etc). The solutes can be small molecules, fragments to proteins and macromolecules.

The SR method, as a light scattering technique is both accurate and rapid and requires very little amount of compounds. It uses the solvent that is native and fundamental to chemistry of solubility and aggregation. The SR method is sustainable and economical, it does not require the use of filters, filter-plates, vials, columns, and minimizes the use of chemicals and consumables.

More information – Download the SR Method whitepaper here