Galactitol (dulcitol) is a sugar alcohol, the reduction product of galactose. Galactitol is known to be the major toxic metabolites of galactose. Deficiency of any one of three possible enzymes involved in the metabolism of galactose: galactokinase, transferase or epimerase results in galactosemia. Any single deficient enzyme can result in cataract through the accumulation of galactitol in the lens. Accumulation of galactose and galactitol within the lens cells leads to an increase in intracellular osmotic pressure and an influx of fluid in the lens. Kinoshita was the first to demonstrate the hyperosmotic effects of intracellular sorbitol or galactitol accumulation and to postulate that the resulting cellular swelling can lead to increased membrane permeability and a series of complex biochemical changes associated with sugar cataract formation. The excretion of abnormal quantities of galactitol in the urine of galactosemia patients is characteristic of this disorder. A patent claims galactitol as carrier for the therapeutic agent since galactitol enhances the chemical and physical stability of the drug and allows faster reconstitution of the formulation in water than mannitol.