Zeta potential as an indicator of stability is only relevant if the only mechanism preventing aggregation is electrostatic. If your emulsifiers introduce other mechanisms (e.g., steric effects), zeta potential won't be helpful. In addition, it is important to know two other important pieces of information in order to assess the meaning of zeta potential even in a charge-stabilized system:

1. The magnitude of the attractive forces

2. The ionic strength of the dispersion medium (since this affects how close particles can approach

Finally, the aggregation rate will be influenced by:

1. The size of the particles (since this affects the diffusion rate)

2. The concentration of the particles (since this affects the probability of diffusing particles approaching close enough to other particles in a given time frame).

As you can see, assessment of stability requires more than just measuring zeta potential (though instrument manufacturers would like you to believe that such instruments allow you to solve all your stability issues in 30 minutes!)

@john Francis miller sir you add meaning full knowledge got it sir .

Your highness

Hello Sir!

In continuation of @john Francis i would like to add few points into it, Sir, you have enlisted very effective points but in addition to stearic and electrostatic interaction ,drug delivery plays a vital role in defining charge and size of the particle. For example: If you need to deliver any anionic body i.e., nucleic acids etc. you cannot continue with the charge you mentioned i.e., -10.whereas in conventional drug deliveries without anionic counter parts your can proceed with this specific zeta potential depending upon the target binding efficiencies. For your ready reference, i am attaching one such approach, kindly have an overview. Article Lipid-based Nano therapeutics for siRNA delivery