Abstract: A pore-size graded, packed cascade barrier bed, flow-through cell for the measurement of dissolution behavior. The cell containing a porous packing of insoluble multi-particulate solids is designed to retain, in a flow of solvent, particulate solids such as contained in suspensions and slurries or as a result from the disintegration of tablets, capsules, or the like. The vertical bed is packed in discrete layers with uniform sized, inert particles, progressing from layers of small particles at the bottom to layers of large particles at the top. The solid material to be dissolved, when introduced at the top, is carried down into the bed by gravity and the downward flow of the solvent, separated into particle size fractions by the bed, and held in contact with the flowing solvent. The cell is used in conjunction with suitable means for pumping and controlling solvent flow, for controlling ambient and solvent temperature, and for measuring the concentration of the dissolved solid in the effluent solvent.