When a patient has no alternative towards treatment of disease then Magnetic microspheres come into view.Magnetic Microspheres have basically two advantages that is Reticuloendothelial clearance can be minimised and target site specificity can be increased.For Drug targeting, various carrier systems have been exploited like liposomes, nanospheres, microspheres, macromolecules etc. The difficulty of targeting drugs in vivo using these carrier systems is that the body contains 3 major tubes: the vascular, extracellular & intracellular compartments. Despite having several advantages, one most important problem to this field is that all the systems so far developed, give release rates that are either constant or decrease with time. Microspheres are successfully utilized for drug targeting but they show poor site specificity and are rapidly cleared off by RES (reticuloendothelial system) under normal circumstances.Improvement of patient compliance can be accomplished by this method. ... Это и многое другое вы найдете в книге Preparation and Evaluation of Magnetic Microspheres of Mesalamine (Satinder Kakar and Ramandeep Singh)