ON WHICH PRINCIPLE?

These pseudomolecular associations mainly occur in poorly dissociative solvents and behave thermodynamically in such solvents as neutral molecules. They hardly ever exist in water, given its dissociative power, and ions are isolated; however free ions and ion pairs are always in equilibrium:
In water (ε₀ = 78), Kd is really high, and ion pairs (when soluble in such a medium) are practically negligible.

If A- and B+ are voluminous ionic species with a relatively high mass (>150 daltons) and sufficiently hydrophobic, it is possible to extract the ion pair using an organic solvent.

In this case, the size and structure of the associated ion(s) are such that there can hardly be any hydration layer at the periphery, meaning that dissociation is not possible.