Coulter Counter measurements of solubility and dissolution rate of sparingly soluble compounds using micellar solutions

Abstract

Abstract A Coulter Counter, Model TAII, was used to determine both solubility and surface specific dissolution rate of two sparingly soluble materials suspended in micellar solutions. The equilibrium solubility increased linearly with surfactant concentration, thereby making it possible by extrapolation to characterize materials with an aqueous solubility down to 1 ppm or less. At high concentrations (>0.1% w/v) the effect of surfactant concentration on the surface specific dissolution rate was less than that predicted from the increased bulk solubility.