NEW RADIOPAQUE POLYHEMA-BASED HYDROGEL PARTICLES

New iodine-containing polymeric hydrogel particles were prepared by su spension radical copolymerization of 2-hydroxyethyl methacrylate (HEMA ), -(methacryloylamidoacetamido)-2,4,6-triiodobenzoic acid (MABA) and ethylene dimethacrylate (EDMA) in an aqueous medium using azobisisobut yronitrile as an initiator and magnesium hydroxide as a suspension sta bilizer. To impart porosity to the product, cyclohexanol and 1-dodecan ol were added as inert diluents to the polymerization mixture. Particl es containing 27 wt % iodine produced radiopacity sufficient to observ e a clearly visible X-ray image. The equilibrium swelling behavior of the particles in water was characterized. Swelling of the particles dr amatically increased by converting the acid groups of MABA into their Nat form. The more MABA the copolymer particle contain, the higher is their swelling in the Na+ form. (C) 1997 John Wiley & Sons, Inc.