Pharmacokinetics and hematotoxicity of a novel copper-based anticancer agent: Casiopeina III-Ea, after a single intravenous dose in rats

Casiopeina III‐Ea is a mixed chelate copper (II) complex that has shown cytotoxic and antitumor activity in vitro and in vivo. The aim of this study was to investigate the pharmacokinetics of total copper derived from casiopeina III‐Ea administered by intravenous bolus injection to Wistar rats. Other objective was to evaluate the hematotoxicity produced by this compound in those animals. Wistar rats received a single intravenous dose of 4 mg/kg of casiopeina III‐Ea. Blood samples were taken and pharmacokinetics evaluated. Furthermore, erythrocyte copper levels were determined to identify a potential target and Zn levels were analyzed to determine a possible change. For the evaluation of hematotoxicity, both blood and urine samples were collected for hematological and biochemical analyses; moreover, Fe determination was performed. Blood copper and zinc levels, red blood cell copper levels as well as copper, zinc, and iron amounts excreted into urine were analyzed by ICP‐MS. The blood concentration–time profile of copper derived from casiopeina III‐Ea was fitted to a two‐compartment model with a zero‐order input. Cumulative amounts of Cu, Zn, and Fe excreted into rat urine after administration of casiopeina III‐Ea were different with respect to control. Hematological and biochemical data indicated a hemolytic toxicity. Pharmacokinetic analysis of total copper derived from casiopeina III‐Ea provided a general knowledge about distribution and elimination process of this compound. Additionally, the systemic exposure of the copper derived from casiopeina III‐Ea accounts for the hematotoxicity of this complex at test dose.