Supersaturating formulations are commonly judged by how high and how long dissolved drug concentrations remain above equilibrium solubility. That description is incomplete because the pharmaceutical value of supersaturation depends on competing rates: generation of the supersaturated state, redistribution into drug-rich or precipitated phases, and removal of molecularly available drug by absorption. Evidence from amorphous solid dispersions, cocrystals, lipid-based systems, biorelevant transfer models, and dissolution–permeation platforms shows that identical-looking concentration advantages can have different consequences when nucleation kinetics, gastrointestinal composition, phase state, permeability, and absorptive sink strength differ. A high apparent dissolved concentration may coexist with reduced thermodynamic activity, rapid precipitation, or poor membrane flux, whereas short-lived supersaturation may still support substantial absorption for highly permeable drugs. This Formulation Perspective therefore argues for interpreting supersaturation as a time-dependent mass-transfer problem rather than as a dissolution endpoint. The proposed supersaturation–precipitation–flux framework separates generation, phase loss or reservoir formation, and absorptive removal while retaining formulation, gastrointestinal, and assay boundary conditions. Its purpose is not to replace dissolution testing, but to identify when dissolution alone is insufficient for formulation ranking and when coupled kinetic and flux measurements are needed.
IJPRAS
