Effect of bicarbonate, phosphate, and saline lavage solutions on the dissolution of ferrous sulfate tablets

The liberation of iron from ferrous sulfate tablets was studied in vitro to determine the influence of typical lavage solutions used to treat iron poisoning. In separate experiments, one or six tablets were immersed in simulated gastric fluid that contained bicarbonate, phosphate, or normal saline. The amounts of iron liberated from the single tablet studies were not significantly different among the three lavage solutions. In the 6-tablet experiments, the liberation of iron was significantly (p less than 0.05) retarded by bicarbonate and phosphate lavage solutions compared to saline. The clinical significance of these findings is difficult to assess without correlation in vivo. Studies comparing the lavage solutions for iron poisoning should consider the wide intertablet variability in dissolution, the retardation of iron liberation from multiple tablets by bicarbonate and phosphate, and the use of iron tablets instead of iron solutions.