Unconventional separation of arsenic trioxide from unused aqueous chemotherapeutic agents by direct evaporative crystallization

An unconventional arsenic trioxide (As2O3) recovery process for unused injectable aqueous chemotherapeutic agents for leukemia treatment, having a concentration of 2 mg of As2O3/mL of H2O, was used as a case study by evaporative crystallization in a closed system under the pressures of 0.4, 0.7 and 1.0 atm. The yields for As2O3 solids recovered were 60 to 90 wt% with a purity in conformity with the As2O3 standard based on an HPLC assay. The recovered As2O3 solids were determined to be the arsenolite phase by PXRD with a particle size range of <10 μm.