beta-Cyclodextrin was coupled to the -OH group of 2-hydroxyethyl methacrylate using hexamethylene diisocyanate. Segmented polyurethane and the modified monomer were dissolved in dimethylacetamide and subsequently heated to about 80 degrees C in the presence of AIBN to polymerize the modified monomer to form a semi-interpenetrating network. The potential of the new polymer as a membrane was evaluated by studying the sorption of testosterone and progesterone. The preliminary data showed that the polymer could differentiate structurally close molecules with some degree of selectivity, indicating the possibility of exploring further the polymer, particularly as a membrane.