OptiPrep is a sterile and endotoxin tested solution of 60 % iodixanol in water with a density of 1.320 g/ml. Iodixanol was developed as an X-ray contrast medium an has therefore been subjected to rigorous clinical testing. It is non-ionic, non-toxic to cells and metabolically inert. Iodixanol solutions can be made isoosmotic at all useful densities, this solutions have low viscosity and osmolality.
The high density of OptiPrep facilitates the fractionation of cells by flotation from a dense load zone through either a continuous or discontinuous gradient or through a simple density barrier.