ABSTRACT:The reactions employed for coupling anti-platelet and other drugs to hydroxylic polymers are described. The drugs include the prostaglandin analogue 5-(6-carboxyhexyl)-1-(3-cyclohexyl-3-hydroxypropyl) hydantoin (BW 245C) and the phosphodiesterase inhibitors dipyridamole and theophylline. Polymers studied were poly(vinyl alcohol), dextran, and poly(ethylene glycol), and coupling was effected either with the aid of halo-isocyanates or by a two-stage process using carbonyl diimidazole. These novel reaction sequences appear to have wide applications.