SM-153 METALLIC HYDROXIDE MACROAGGREGATES - AN IMPROVED PREPARATION FOR RADIATION SYNOVECTOMY

A new type of preparation employing Sm-153 metallic-hydroxide macroagg regates (Sm-153-MHM) for radiation synovectomy was developed. The radi opharmaceutical was prepared by reacting the aqueous solution of (SmCl 3)-Sm-153 with sodium borohydride solution in 0.5N NaOH. Microscopic a nalysis showed that Sm-153-MHM mean particle size was 4 mu m (range 1- 15 mu m) avoiding the formation of fine particles (< 1 mu m) which wer e observed in Sm-153-hydroxide macroaggregates preparations (Sm-153-HM ). Also, suspension properties as sedimentation rate, were better for Sm-153-MHM than for Sm-153-hydroxyapatite and Sm-153-HM. Biological st udies in normal rabbits demonstrated high retention into de Knee joint space even at 48 h after Sm-153-hydroxyapatite and administration of Sm-153-MHM(> 99%).