Preparing nanoparticles by Salting –out Method

In this method as shown in Figure; acetone is chosen as the water-miscible organic solvent because of its pharmaceutical acceptance with regard to toxicity. The method consists of the addition of water soluble polyvinyl alcohol in a highly concentrated salt solution in water (aqueous phase) to a polymer solution in acetone (organic phase). Although acetone is miscible with pure water in all ratios, the high salt concentration of the aqueous phase prevents mixing of the phase. After emulsification, the addition of pure water in a sufficient quantity causes acetone to diffuse into the aqueous phase, resulting in the formation of nanoparticles.

 

Schematic representation of Salting out technique

Advantages of salting out technique

The main advantage of this technique is that it minimizes stress to protein encapsulants, it doesn’t require an increase of temperature and therefore maybe useful when heat sensitive material has to be processed.

Disadvantages of salting out technique

It is exclusively applicable to lipophilic drugs and extensive nanoparticle washing steps.