Chemotherapy of Experimental Schistosomiasis Mansoni: Influence of Dimercaptosuccinic Acid on the Toxicity and Antischistosomal Activity of Sodium Antimony Dimercaptosuccinate and other Antimony Compounds in Mice

Effect of four thiol-containing chelators on disposition of orally administered mercuric chloride

Acute toxicity and the disposition of inorganic mercury depends on the route of exposure. Most previous studies on effect of chelators on inorganic mercury toxicity and toxicokinetics employed parenteral administration of both metal and chelator. However, the most prominent routes for human inorganic mercury exposure are the oral or pulmonary. BAL was previously considered the drug of choice in human intoxications with most heavy metals. This recommendation has been questioned during recent years due to the advent of the less toxic hydrophilic BAL analogues DMSA and DMPS. The present study, using oral administration of HgCl2 labelled with 203Hg, demonstrates that DMPS is superior to the other chelators in preventing mortality. Moreover, both DMSA and DMPS are superior to BAL and NAPA in alleviating acute toxicity and in preventing the undesirable distribution of orally administered mercury, especially to the brain. Further, oral administration of these chelators were more efficient than parenteral administration in reducing whole-body retention and organ deposition of orally administered mercuric chloride, most likely due to the prevention of intestinal uptake of mercury.

New developments in therapeutic chelating agents as antidotes for metal poisoning

An examination of the studies on therapeutic chelating agents that have been carried out during the last decade reveals that extensive efforts have been made to develop compounds superior to those previously available for the treatment of acute and chronic intoxication by many metals. These metals include primarily iron, plutonium, cadmium, lead, and arsenic, but also many other elements for which acute and chronic intoxication is less common. These studies have revealed the importance of several additional factors of importance in the design of such compounds and have led to many new compounds of considerable clinical promise. An additional development has been the introduction of previously developed chelating agents for use with certain metals on a broader scale.